the passion for cacti and other succulents

eduart zimer

succulent flora of rangitoto islandfollowed by whakaari - the white island

S5February

2015

ISSN

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3987

Summary 2 - XEROPHILIA • Special Issue, No. 5, February 2015 | ISSN 2285-3987

summary

Cover 1

Calystegia soldanella at Boulder Bay.

photo by the author

Cover4

Rangitoto Island seen from Milford Beach.

photo by the author

Founders: Eduart Zimer • Dag Panco • Valentin PoseaEditor: Eduart ZimerEditorial team: Eduart Zimer - EN edition • Valentin Posea - RO edition • Pedro Nájera Quezada - SP edition & Field researches • Dag Panco - PR & Graphic • Miguel Angel González Botello - Cartography.Supporter: Mihai Crisbășanu

Grafic layout based on Andrea Cattabriga's pattern.Editorial team's e-Mail: xerophilia@xerophilia.ro.

All rights reserved – no part of this publication may be reproduced in any forms or by any means, without written permission of the Editor. All copyrighted photographs have been used under the Creative Commons Attribution 4.0 International license.

S5 Febr

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2015

Eduart is a cacti, succulents and xerophytes en-thusiast born

in Romania. He dis-covered « the world of the cacti » only at the age of 40, but this was to become in short time his main area of interest. He moved to New Zealand 12 years ago, which allowed him a different ap-proach and better un-derstanding of nature

and ultimately contributed to the diversification of areas of interest: plant naturalization (especially of succulent plants), vegetation successions and ecology of coastal habitats. He joined cactusi.com in 2004, and is also member of Cactus and Succulent Society of NZ since 2006 and of International Cras-sulaceae Network since 2008.

Part 1. Rangitoto IslandI. Introduction

II. A brief natural history11 · Early accounts on vegetation status14 · Vegetation colonization15 · The biggest early threats19 · 20th century massive human interference24 · Shipwrecks25 · Establishing wild life

III. Vegetation patterns29 · The succulent haven: the coastal strip38 · A rich additional herbal flora43 · Eco-climatic characteristics

IV. Species walkthrough47 · Aizoaceae53 · Amaranthaceae55 · Araceae57 · Asparagaceae61 · Asteraceae62 · Balsaminaceae63 · Brassicaceae64 · Cactaceae65 · Commelinaceae66 · Crassulaceae99 · Euphorbiaceae

100 · Geraniaceae104 · Orchidaceae 105 · Piperaceae106 · Xanthorrhoeaceae

V. Some other very interesting species

VI. Notable absences

VII. Conclusions

Part 2. WhakaariWhite Island 143

part 1.

a review of the succulent flora of rangitoto island hauraki gulfnew zealand

4 - XEROPHILIA • Special Issue, No. 5, February 2015 | ISSN 2285-3987Contents

View of the Hauraki Gulf from near the summit

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5 - XEROPHILIA • Special Issue, No. 5, February 2015 | ISSN 2285-3987Part 1. - I. Introduction

I. introduction

The young volcanic island of Rangitoto is always a very interesting subject for nature lovers in search of unique habitats and, as far as I am concerned, it presents

a particular interest for its rich succulent flora as well. Being close to New Zealand’s major urban centre, Auckland, and therefore easily accessible, Rangitoto was even more prone to become the subject of many studies, articles and monographs. However, except for W.R. Sykes’ monographic article (Sykes, 1992) little has been written specifically on the island’s succulent flora. Being a cactus and succulent enthusiast myself and because since 2006 I was first charmed by and then became passionate about Rangitoto, I think it is highly time for me to write this review of its succulent flora. More, I will try to present brief information on the natural history, wild life and other plant species (both native and introduced) as all elements are not only intertwined, but strangely unique.

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Auckland City seen from halfway Summit Track

Although primarily focusing on the exotic succulent flora I will not circumvent the few native species. Odd enough, although a welcoming land for exotic succulents from all over the world, New Zealand native flora does not include many succulents, probably due to the troubled climatic past. In fact especially the coastal habitats lack native succulent species and are very exposed to the invasion of more dynamic exotic species.

Documented speciesHowever, it is impossible for me to produce a comprehensive list of extant species, for several reasons. First, as it already happened with few non-succulent invasive plants, some trouble makers (might) have been already eradicated by the Department of Conservation (DOC) – one good example is Tradescantia fluminensis, reported as eradicated few years ago. Secondly, other plants could already become, in time, naturally extinct – this could be the case with Echeveria ‘Set-Oliver’. Third, some earlier records include misidentifications (e.g. Aeonium arboreum). I will therefore largely exclude obvious errors, but still mention few dubious records if no convincing

counter-arguments or if these errors have been repeatedly mentioned and became “public knowledge” so to speak, however, trying to clarify their status.

Anyway, all species documented at any point in time will be on my list even if not encountered anymore in later years; however, this does not mean they are still extant. And finally fourth, in the absence of a clear definition of succulence (which I’m not willing to debate now), I have possibly excluded, both intentionally and unintentionally, various technically succulent or, worst case, sub-succulent species of the rather “grey area”, focusing instead on species generally "considered" succulent by plant lovers.

Mainly geophytes are not that well represented in my account. Similar to W.R. Sykes, I have myself interpreted the word succulent “fairly loosely” and included maybe “a few plants which could be best described as semi-succulent” while omitting other, such as some geophytes as mentioned above. But it comes down I guess to what’s one’s definition of “succulent plant” is, where this starts and where does it end – I have saved this debate for later.

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Main reference worksI have to mention that W.R. Sykes’ 1992 account is the only coherent paper on succulent plants of Rangitoto. While somewhat outdated in certain aspects and missing few interesting species, it still was a true and extremely useful field guide for me, together with the much more comprehensive Natural History of Rangitoto Island (Wilcox, 2007), unfortunately more statistical and illustrative than descriptive or analytical and not focusing at all on the succulent flora of the island. However, the latter relies apparently also on personal comments and unpublished notes of members of the New Zealand and Auckland Botanical Societies, not always well documented, and not on herbarium specimens. As a result some names pop up only in Wilcox (2007) in the species lists, with no references available, e.g. Opuntia monacantha.

However, in my attempt to be accurate in all information provided I have consulted in the end well over 100 reference works, articles and websites, of which only a part, the most important, are listed below. My personal experience was added hopefully for the best, a total of 12 trips to Rangitoto between 2006 and 2014 totalling over 90 hours of field work and habitat study. I started being interested only in the succulent flora, but ended up witnessing a magic world, reaching far beyond my primary intentions. This will become obvious as you will scroll through this paper.

Hauraki Gulf Islands seen from near Rangitoto summmit. In the far background you can see the mountain ranges of Coromandel Peninsula.

A common Rangitoto vegetation pattern: barren lava fields surrounded by well estabished, slowly advancing Metrosideros excelsa thickets.

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The narrow channel between Motutapu (in the backgrund) and Rangitoto at high tide. Note the composite exotic vegetation of the shore, dominated here by Agapanthus. Above: Motuihe Island seen from near Rangitoto summmit. Note the diversity of the canopy, nowhere else to be seen in New Zealand.

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Drying sharks on Rongitoto, a watercolour by Charles Heaphy dated around 1850. After fishing expeditions, the shark carcasses - a staple food for many Maori - were hung on racks to dry. Note the "well-wooded" shore areas.

An ink and watercolour painting by Charles Heaphy which shows the volcanic cone and the crater of Rangitoto in the early 1850’s and is considered by some hard evidence supporting the late colonization theory.

A photograph taken by Rev. Dr. John Kinder in 1869 is apparently also supporting the late colonization theory, even better than the above mentioned painting … in fact this is nothing but popular tradition.

II. a brief natural history of rangitototitletitle

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Rangitoto Island is one of the many monogenetic volcanoes of the Auckland volcanic field, rising to 260 m above sea level and having a surface of roughly 2,800

hectares. The name Rangitoto originates from a phrase: “Nga Rangi-e-toto-ia-a-Tamate Kapua”, meaning “the days that Tamate Kapua bled”, shortened in time to Rangitoto. The incident refers to a fight between two Maori iwi leaders, Tamate Kapua and Hoturoa, the commanders of the Arawa and Tainui canoes respectively, when Tamate Kapua was severely injured.

This is probably the original meaning as it has a solid linguistic support. A derivative meaning, however, strongly coined over the time is “blood red sky” (the name Tamate Kapua means literally “killed clouds”), which suggests that the Maori settled on the neighbouring Motutapu Island would have witnessed major eruptive events. Although etymologically wrong, it is factually probably correct: footprints covered by volcanic ash have been discovered on Rangitoto. The Maori must have witnessed, at least at some stage, major volcanic activities on the island.

Although they inhabited only the neighbouring Motutapu Island, temporary operations were carried out on Rangitoto as well.

There is an amount of uncertainty in regards to the timeframe of the main volcanic eruption, although it is almost sure that the early 1300’s have witnessed if not the emerging of Rangitoto from the sea, than definitely a sustained volcanic activity on the island, including lava flows and ash emissions.

There is a split opinion on this, some geologists maintain that for the bulk of the lava flows shaping the island as we know today it took only 20 years, other extend this period to over 200 years. Clarkson (1990) maintains that “the volcano appears to have been active between 850 AD and 1800 AD with a maximum lava flow activity around 1300 AD”. Eruptions have not occurred past 1500 AD, but initial lava flows were followed by ash emissions “which filled most of the crevices and shallow hollows”. Some other accounts place the peak of the volcanic activity a bit earlier, before 1250 AD or even before 1200 SD. The summit was measured at 259 metres above sea level.

One thing is sure: this is how it started, from the barren basaltic lava flows colonized at some stage after cooling by Nitrogen fixing lichens.Right: The lichen Usnea rubicunda - Red beard lichen - opening the way.

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Early accounts on vegetation statusPlant colonization might have started relatively soon after the lava fields have cooled, possibly within decades; however, the initial moment – a key factor in all colonization models - is largely unknown. Volcanic activity has continued for a while, almost certain witnessed until the 1780’s, without lava flows but at times with sustained ash and tephra emissions accompanied by fumes. This volcanic activity has definitely influenced the pace of vegetation colonization; however, the timeframe is important as initial colonization is always slower compared to vegetation re-generation. One thing is sure: this is how it started, from the barren basaltic lava flows colonized after cooling by lichens. As most lichens are capable of nitrogen fixation the next step, the establishment of mosses and later on of vascular plants, got the perfect kick start.

Even if we cannot ignore the huge impact of man introduced plants over the last 100 – 120 years, I would rather suggest that, considering the impressive diversification of vascular plants established on the island, the colonization process

Typical Rangitoto vegetation pattern: large barren lava fields surronded by abrupt vegetation thickets.Above: In most cases there is no transition between the established Metrosideros, the rich sub-canopy and ground vegetation and the barren lava fields. In this picture you can clearly see the colonizing lichen patches. Below: Later A very young pohutukawa (Metrosideros excelsa) growing with no support on the lava fields.

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could have started earlier than 400 – 500 years ago, despite the possible marginal volcanic activity in the cone area. On the shores, in more sheltered pockets, vascular plant colonization may have started as early as 1400’s.

One of the earliest accounts is that of the French traveller Jules Dumont D’Urville, who noted in 1827 that Rangitoto looked “well-wooded” if compared with the mainland (and don’t forget that Rangitoto used to be a somewhat active volcano until few decades earlier). D’Urville has sailed down the Rangitoto channel observing the north-eastern coast of Rangitoto Island which even today is less vegetated than the rest – this would suggest that the vegetation of Rangitoto wasn’t too different from what it is today (Julian, 1992).

D’Urville’s impressions may have been very

accurate and are somehow confirmed by the detailed journal entries of Rev. Henry Williams who just very few years later, in 1833, camped on Motutapu and made two trips to Rangitoto.

His account suggests that the vegetation on Rangitoto was certainly less developed than today; however, “bushes and shrubs appear to cover the whole island” (Julian, 1992).1886 accounts published in periodicals of the time extensively quoted by Butler (2001) mention shrubs growing luxuriantly and flowering pohutukawa trees which “remind one of the richness of the tropical vegetation”, “(…) shrubs and some forest trees grow and flourish over two thirds of the surface the roots penetrating the crevices of the scoria and finding probably far down the decomposed washings of the rock”.

Dense forest-like vegetation along the Summit Road.

Light bush and grassland at Wreck Bay … "reminding of the richness of tropical vegetation". According to some accounts it was pretty much the same 150 years ago.

Light young forest on the path to Wreck Bay with an extremely interesting diversifying under canopy vegetation.

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Questions on the vegetation developmentAccording to Kirk (1879) “the volcanic island of Rangitoto (…) possesses greater interest to the botanist than any other island in the group. This arises less from a copious flora - although the number of species is comparatively large – than from the remarkable state of the ligneous vegetation, which exhibits the utmost luxuriance of foliage and flowers on the most diminutive specimens, and from the peculiar conditions of growth, most of the plants springing directly from the face of the rocks or from the crevices between them. ”Both accounts suggest that 150-200 years ago Rangitoto was already relatively well vegetated, which almost implies that vegetation started to establish at least 300-400 years ago, if not even earlier.

But even if we accept that vegetation was less developed in the early 1880’s, it was still present “in much the same form as today” and the belief “that Rangitoto was almost completely bare of vegetation from as late as the latter part of the 19th century” is nothing but popular tradition (Julian, 1992). To this myth may have contributed another ink and watercolour painting by Charles

Heaphy which shows the volcanic cone and the crater of Rangitoto in the 1850’s and is considered by some hard evidence supporting the late colonization theory. In fact, it could be just an “artist impression” as it is quite contrasting with the accounts presented above (not to speak that few “trees” can be seen scattered in the summit area).

Another photograph taken by Rev. Dr. John Kinder in 1869 is apparently also supporting the late colonization theory, even better than the above mentioned painting. But unfortunately – beside the extremely poor quality which makes this picture highly unreliable - it presents the island from a very deceptive angle with focus on the barren shore and pointing above to the less vegetated cones area – quite blurry, but visible covered in some vegetation.

It largely hides therefore exactly the most vegetated parts of the island (at that time) – the low basaltic lava fields making up more than 80% of the total surface, and described as “well-wooded” by D’Urville four decades earlier. Inopportunely, these two “visual” accounts had a huge impact, as it happens with visual media, endorsing the less probable theory.

Senecio angulatus, here in Napier, smothering a relatively massive Opuntia monacantha.

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fewer chances to penetrate an existing compact Metrosideros forest or even young scrub.

Even the grounds of the intended botanic garden are situated right beneath the summit area and quite far from the lower parts of the island indicating indirectly that there were no significant un-vegetated areas available closer to the shoreline, and large enough to support such an ambitious project.

It makes completely sense that vegetation of Rangitoto started quite early in the history of the island, but without having a massive and immediate impact. It has very probably progressed slowly for many decades or even few centuries, building up its maximal momentum only shortly after the volcanic activity on Rangitoto has completely ceased (and this could have been close to the turn of the 19th century) and therefore didn’t have the time and the opportunity to produce old vegetation relics able to certify a considerable age.

Vegetation colonization progressed initially very slowTo bring all this to a conclusion - in my opinion it is highly likely that the vegetation of Rangitoto covered in the early 1800’s the lower parts of the island in pretty much the same way as today, only in young scrub, while the summit areas were possibly much less vegetated, probably as a result of the ongoing volcanic activity (not necessary lava flows, but more or less intermittently steam, gas and possibly ash emissions) until the 1780’s, but not completely barren. A good tip gives us two of the widely established plants of the summit area (and not in the lower parts of the island) - Erica lusitanica (Ericaceae) and Hypericum androsaemum (Hypericaceae) – introduced in 1915 by the ambitious botanical project driven by Mr. Leary and Mr. Wilson. Their rapid but relatively localized dispersal would have been embarked on less vegetated grounds I think and would have had

Erica lusirtanicasu

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The biggest early threats: browsing mammals and wallabies…Until the mid-1800’s Rangitoto was virtually an untouched habitat. A certain pressure on habitats existed since the early years of European settlements, caused by the introduction of alien plants or brutal transformation of natural habitats in farmlands or pastures – but this wasn’t the case with Rangitoto. In early years the biggest threat came from the mammals established on Rangitoto, mainly possums (Tricosurus vulpecula) released on the neighbouring Motutapu Island in 1868 by Sir George Grey and the brush tailed rock wallabies (Petrogale penicillata), animals present in significant numbers at some stage, now eradicated - which used to perturb the vegetation development by destroying the young shoots (Julian, 1992). Very fortunately goats (the worst animal pest especially on islands) were not present very probably due to the fact that vegetation density and patterns could not sustain grazing animals and were not introduced, but fallow deer

(Dama dama) was introduced on Motutapu in 1862 by Robert Graham (who owned the island at that time) and reportedly some of the animals moved across to Rangitoto on low tide. A different kind of damage was made by the ship rat (Rattus rattus), Norwegian rat (Rattus norvegicus), common house mouse (Mus musculus), feral cat (Felis cattus) and rabbit (Oryctolagus cuninculus) which were all still present in the early 1990’s (Miller et al, 1994); especially the rats were a real threat for the very few birds nesting on the ground. On one hand the vegetation on Rangitoto couldn’t support large numbers of birds, on the other hand their eggs were eaten especially by rats so that larger populations couldn’t establish anyway. In the 1980s the wallabies population was estimated at 2,000 animals (Wilcox, 2007), “but they were in poor condition and did not breed very prolifically due to the harsh, arid conditions.” However, this population was large enough to produce damage to new growth of Metrosideros excelsa and Coprosma lucida, their preferred food source.

Mustela erminea - photo by Steve Hillebrand, ex Wikipedia.

Petrogale penicillata - photo by Hugh McGregor, ex Wikipedia.

Tricosurus vulpecula - photo by The Brisbane City Council, ex Wikipedia.

Erinaceus europeus.

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All these animal pests were actively controlled by any means (including traps and poisoning) starting with 1990, sometimes accompanied by the harsh critics and bitter disapproval of the animal rights organizations, but in my opinion it was a necessary step for the greater good – the conservation of Rangitoto. Stoats (Mustela erminea) were established on Rangitoto too at that time and hedgehogs (Erinaceus europaeus) were suspected to be also present. The number of all these mammals is relatively low and populations under constant survey, so that there is no immediate pressure here. I have not encountered the presence of such mammals on the island.

Rangitoto Island seen from Devonportsu

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… and don’t forget the humans!However, the biggest pressure came (as usually) directly from humans. Even if the neighbouring Motutapu Island was inhabited since 1840, there was little to no impact on Rangitoto’s vegetation development (except for the mammals already mentioned above) and no significant vegetation exchange took place between the two islands, but after 1872 things have changed. The first significant human activity on Rangitoto started with considerable quarrying that took place on several sites, the operations being owned by private individuals or by the government, but also by the Auckland Harbour Board.

The impact on the environment was direct and unstoppable. Julian (1992) states: “Stone was removed for harbour works, tramways, drainage, and construction work from extensive quarry sites, mostly on the eastern side of the island near Islington Bay. This quarrying ceased in 1929 and was not resumed (Cottrell, 1984). The quarrying resulted in considerable alteration in the rock surface which, in turn, has resulted in different patterns of vegetation in these areas”.

This was just the beginning. In 1890 the island became a recreation reserve and shortly after that,

in 1897, the southern wharf and walking tracks were opened to the public and Rangitoto became a popular picnic destination for Aucklanders. This brought a new problem for the Devonport Borough Council (DBC), the administrator of the island, and this was fire and vandalism that has increased in a short period of time. Financially the DBC wasn’t fit enough to support payments for caretakers or guardians, not to speak of the development and maintenance costs. In order to overcome these problems the DBC has leased parts of the foreshore, especially on the southern and eastern coast, as “campsites” with permission to erect holiday homes – the famous baches of Rangitoto. Although most of them were not permanently inhabited, it is throughout possible that up to 50 people have lived permanently on the island, some of them acting as caretakers and, however, contributing to a vivid lifestyle on Rangitoto. Of course, during holidays and on weekends many more people were visiting the island.

As a result of this increasingly popular holiday destination between 1911 and 1937 a number of 121 baches were built on Rangitoto. Private dwellings established on public land, leading later on to legal disputes.

This used to be a small building siding one of the quarries.

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However, the afflux of people taking by storm Rangitoto lead to another problem. Probably depressed by the view of the barren lava fields the visiting crowds and the few residents tried to enhance their lifestyle and “beauty” the harsh volcanic landscape. “Planting days” were organized in the 1890s when not only the inhabitants but also members of the public were encouraged to bring by ferry their favourite plant with them, and these actions count for the dispersal of several endemic or introduced species on the island.

Young forest at Wilsons Parksu

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20th century massive human interferenceLater on, in 1915, Mr. Leary and Mr. Wilson even started the works for a Botanic Garden, reportedly intended to include also cacti and other succulents, never finished and eventually abandoned as it has happened with many other projects during the troubled times of war. However, due to their efforts we owe few introductions such as the Spanish heath (Erica lusitanica) and tutsan (Hypericum androsaemum) in the summit area. The site is known today as Wilsons Park and is situated very close to the main crater rim.

Another boost was given between 1926 and 1930 when roads have been built using prison labour; basically most of the driveable roads crossing the island were built in this period. Although no major direct influences on the vegetation patterns were caused it is believed that this might have helped the relocation and dispersal of weeds on the road sides and also of browsing mammals, the smooth surface of the roads being (in contrast with the rough surface of the open lava fields) easier to use for long range movements (Julian, 1992).

The last chapter of massive human interference

was WW2, when Rangitoto became a defence area and further constructions have been erected, guns have been installed and – most important – a new road and a Controlled Mine Base were constructed causing the most extensive ever cuttings through the lava fields. Even today the site of the Controlled Mine Base is home for many exotic plants, many of them succulents.

One of the most important works – implying little immediate disturbance of the habitats but opening all ways for animal and plant species exchange – was the passage to Motutapu build for defence purposes.

All of this had a significant impact on the vegetation development and on the vegetation patterns on Rangitoto, even triggering infestations with highly invasive plants in some parts of the island. This problem was acknowledged as early as 1937, but little has been done until after the WW2. There are obviously three sources of alien plants on Rangitoto – deliberate introduction, garden escapes and natural dispersal from adjacent sites (mainly Auckland’s Devonport and Motutapu), however, the latter being the less important dispersal mean, at least in later years.

Ruins of the prison gate.

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Vlad at a private landing near Islington Bay.Inside a WW2 bunker near the summit.

Boatramp and dinghy.Bach 38 - restored.

Restored bach.Abandoned bach near Islington Bay.

The Controlled Mine Base.Old scoria platform.

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The white painted landbrigde between Rangitoto (on the left left) and Motutapu was built for defense logistic purposes, but actually only facilitated species exchange between the two islands. This is the narrowest point (less than 20 metres) of the separating channel. Below: A heaven for vintage booze bottles collectors

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Modern artefact near bach 15su

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Stairway to Heaven

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ShipwrecksThe northern parts of Rangitoto Island (mostly in the shallow waters of Boulder Bay and Wreck Bay) served as graveyard for at least 13 vessels that were dumped between 1887 and 1947. “Some of the older vessels that were made of timber were burnt to the waterline. Later wrecks provided a rich resource for the island's handful of bach owners, who descended on the hulks and stripped them of fittings and timber to incorporate into their holiday homes”. (RIHCT).

Some of the underwater structures serve as scuba diving attraction and it is said to have

helped a variety of sea fauna to establish locally, as it usually happens in such circumstances: “The deeper wreckage just offshore attracts a variety of fish and other marine life and can be appreciated by snorkelling or scuba diving”.

Unfortunately I never managed to stay too long there as there is a serious detour from the main areas where succulent flora – my main target on the island – is widely present.

Being an attraction for many people, in time several adventives species have been established here, originating from seed transported possibly by equipment or on the visitor’s shoes.

Wreck Bay today - Only few pieces from the wreckage can be seen today, however, small artefacts are still easy to find on the shore or in shallow waters. Below left: Wreck Bay 1940s.Below right: My son Vlad with remains of a mosaic - possibly from the sauna of a coastliner.

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Establishing wild life However, in wildlife seems establish and improve on the island… Rangitoto is considered pest free since 2011 according to the DOC website (although monitoring traps continue to be set up in different corners of the island) and ready to become a wildlife sanctuary. In the neighbouring Motutapu the brown kiwi, Apteryx mantelli, was already introduced, while in Rangitoto the presence of the tui bird, Prosthemadera novaeseelandiae, seems to become more significant. Tui flocks used to visit on occasion Rangitoto, especially in spring when the kowhai (several species - Sophora chathamica is common in Rangitoto) flowers, however, during my last two visits I managed to see and hear more tui birds than at any time in the past. Another surprise was, for me at least, a couple of New Zealand pigeons or kererū (Hemiphaga novaeseelandiae) – this was a first time for me. These two birds are essential in seed dispersal and propagation of numerous native species and therefore increased numbers might bring new vegetation dynamics over the next decades.

Other bird species relatively often encoun-tered here are Zosterops lateralis (Silvereye) a small passerine preferring heights or elevated structures, the Variable oys-tercatcher, Haematopus unicolor, which is endemic to New Zea-land, the White-fronted tern, Sterna striata, with recover-ing populations and becom-ing quite common in later years, the Pied shag, Phala-crocorax varius, the Black backed gulls Larus domini-canus, having a massive 1,500 pairs breeding co-lony near Flax Point, the Kingfisher, Todiramphus sanctus, Rhipidura fulig-inosa (fantail) which is common in bushlands, and others. It also was reported (never seen by me here though) that the iconic insect tree weta, Hemideina sp., which is another endemic group of species is present in larger numbers than on the main-land. From the rep-tilian wildlife I have seen only the Rain-bow skink, Lampropholis delicata, several times in scoria rubble near the summit, but didn’t manage to take a decent picture.

Although only one nautical mile from Auck-land, Rangitoto is a unique piece of nature

and has all the chances to become a wild life sanctuary in the years to come. And, we like it or not, the current vegetation setup includes a mix of exotic species, some invasive and therefore unwanted, but not all of them.

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26 - XEROPHILIA • Special Issue, No. 5, February 2015 | ISSN 2285-3987Part 1. - II. A brief natural history of Rangitoto

Tui bird, here at Totara Heights. Zosterops lateralis.

Sterna striata - White-fronted tern - at Rangitoto wharf.

Vanellus miles novaehollandiae, here near Takapuna.

Pied shag, Phalacrocorax varius, near the Controlled Mine Base

Variable oystercatcher (Haematopus unicolor) in the early morning hours at Rangitoto wharf.

Tree weta, Hemideina sp., here in Mt. Wellington, Auckland

Black backed gulls, Larus dominicanus, along the Coastal Track

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Metrosideros excelsa.

III. vegetation patterns and characteristics of the habitat titletitle

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Rangitoto has an almost perfect symmetrical profile no matter from which direction you are looking at the island, with gentle slopes and extended lava fields of rough texture,

consisting of basalt and scoria, in most of the cases very difficult and dangerous to walk on without proper shoes if you deviate from the path.

During sunny days the bare rocks get incredibly hot; this fact combined with the scarcity of available moisture (there are no fresh water sources and no ground water available on the island) make it easy to understand how hostile this habitat originally was, and still is. It is very interesting to see that the vegetation colonization occurs in very distinct steps with almost no transition at all. Relatively densely vegetated areas are abruptly terminated and continued into bare lava fields populated just

by lichens if any, with a transitional strip of 50 – 200 cm only.

The interior of the island is slowly developing into a light bush dominated by Metrosideros trees (Myrtaceae), especially by Metrosideros excelsa, the famous native pohutukawa, one of New Zea-land’s iconic plants, and Metrosideros robusta (Ju-lian, 1992; Wotherspoon, 2002), intermingling with other shrubs and trees all the way up to the 259 m high summit.

A hybrid swarm of the two, described as Met-rosideros sub-tomentosa Carse, was noticed but it is thought that it is progressively backcrossing to Metrosideros excelsa (Julian, 1992). Several ad-ditions – both endemic and introduced plants – complete the characteristic vegetation range of Rangitoto, complex, composite and unique.

At Wreck Bay with Metrosideros excelsa, in the background crop.Below left: Metrosideros excelsa flower.Below right: Metrosideros robusta flower.

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The succulent haven: the coastal stripThe light bush extends, with few interruptions and bare lava fields, from the summit crater to the coast. However, there is no place here for succulent plants, the only one I have seen trying to escape from the shore and finding its way to the inland was in a certain extent Crassula multicava (Crassulaceae) – a real pest here, but even for this plant I wouldn’t say that it actually inhabits sites situated too far from the sea. All other succulent plants are restricted mainly to a 10 – 50 m wide coastal strip, excepting several pockets especially in the southern parts of the island.

The coastal areas are quite different, with marine exposure – and this means first of all more humid and salt laden air. As the bush does not usually

come down to the water line there, is a strip with somewhat less competition allowing many succu-lent plants to establish. Large tussocks halophyte grasses, swarms of Agapanthus praecox ssp. orien-talis (Amaryllidaceae), and in some salt marsh like areas Avicennia resinifera (Acanthaceae), the wood-en mangrove, seem to be the only worthwhile competition. There are obviously three sources of alien plants on Rangitoto – deliberate introduc-tion, garden escapes and natural dispersal from adjacent sites, mainly Auckland’s Devonport and Motutapu Island, however, the latter being the less important dispersal mean. Most succulent species are garden relicts or have spread from abandoned gardens of the former settlements, especially on the eastern and southern coasts.

Dense stands of Agapanthus praecox ssp. orientalis.Above left: The gap between Motutapu and Rangitoto at low tide.Above right: Saltmarsh with young mangroves near Yankee Wharf.

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DistributionIn a nutshell, here are the three different vegetation patterns occurring on the island:

1. The vegetation of the basalt fields. These ar-eas are dominated by Metrosideros excelsa, but also Metrosideros robusta and their hy-brid swarms. Although still very young, Ran-gitoto has the biggest pohutukawa popula-tion in New Zealand. This light bush is not very compact, nor continuous, there is ac-tually a collection of micro-environments, sometimes with very distinctive features, al-lowing other broadleaf species to establish, which deepens local characteristics, for ex-ample dense groundcover patches of Kidney

ferns, Trichomanes reniforme, (Hymenophyl-laceae) with localized occurrence, especially in the southern part of Rangitoto at Kidney Fern Glen. Pohutukawa is by far the most common vegetation type, covering in 1981 ca. 57% of the island (Julian, 1992) and being usually the dominant species where it occurs. Other common vascular species are Genios-toma ligustrifolium (Loganiaceae), Coriaria ar-borea (Coriariaceae), Pseudopanax arboreus (Araliaceae), Griselinia lucida (Griseliniaceae), Knightia excelsa (Rewarewa tree, Proteaceae), Leptecophylla juniperina (Ericaceae) and few others, including a variety of ferns, mosses and lichens.

Griselinia lucida, fruits.

Leptecophylla juniperina.Trichomanes reniforme, patches on the path to Wreck Bay.

Pseudopanax arboreus.Geniostoma lingustrifolium.

Griselinia lucida.

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Mosses, Geranium purpureum and Astelia seedlings

Asplenium oblongifolium.

Knightia excelsa - Rewarewa tree.

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Coriaria arborea.

Coriaria arborea, flowers.

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2. The vegetation of the scoria cones is domi-nated by kanuka, Kunzea ericoides (Myrta-ceae) and manuka, Leptospermum scoparium (Myrtaceae), especially on the eastern slopes, but also other scrubs like Myrsine australis (Myrsinaceae) and tree daisies, Olearia spp. (Asteraceae) are very common. There are also two introduced species with very high occur-rence, Erica lusitanica (Ericaceae) and Hyperi-cum androsaemum (Hypericaceae), both es-capes from the intended botanical garden. The vegetation of the volcanic cones has nowadays the appearance of a light bush, a mixture of several plant species, including scattered kauri trees, Agathis australis (Arau-cariaceae) and, again, Coriaria arborea espe-cially along the tracks. The scoria cones area occupies less than 15% of the total surface.

Rangitoto main crater.Below left: Leptospermum scoparium - Manuka.Below right: Leptospermum scoparium, flower.

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Olearia furfuracea.Below: Rangitoto main crater seen from the sea.

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Agathis australis - kauri tree - in the crater cone.

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3. The vegetation of the shores. The typical veg-etation consists, depending also on the shore characteristics, of various halophytes, which also occur locally forming from dense iso-lated mounds to large patches covering the salt marsh area. This is a very friendly strip for plants with halophytic and or xerophytic adaptations, including all succulents treated here. As the human settlements were at or in the proximity of the shores there is also a high incidence of garden escapes, from gar-den flowers to succulent plants, and from

bushes to trees. Fortunately most of them are confined to this area and have not ad-vanced to the inner parts of the island, with the exception of path and road sides. How-ever, this is by far the most composite veg-etation type of the island, and unfortunately prone to be occupied by aggressive coloniz-ers such as Ulex europaeus (gorse, Fabaceae), possibly the worst pest in New Zealand. It didn’t happen here yet, except few patches only, but it happened elsewhere in similar situations.

Sparsely vegetated lava slabs at Wreck BayBelow: The native grass Austrostipa stipoides near Yankee wharf.

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At Gardiners Gap. Below: Ulex europaeus - local infestation along the Islington Bay Road.

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A rich additional herbal floraHowever, in all three distinct vegetation type areas mentioned above, in clearings or less vegetated corners, in places with less competition from strong or fast growing species, or less exposed to the mercy of the elements, as a ground cover or sub-canopy element, there is a rich herbal flora, starting with the smallest herbs and grasses to medium sized shrubs, comprising some unexpected introduced or native species such as: Centranthus ruber (Caprifoliaceae), Senecio lautus ssp. maritimus (Asteraceae), Centaurium erythraea (Gentianaceae), Thelymitra longifolia (Orchidaceae), Iris x germanica var. florentina (Iridaceae), the non-succulent Euphorbia peplus (Euphorbiaceae), Antirrhinum majus (Plantaginaceae), Myosotis sylvatica (Boraginaceae), Geranium purpureum

(Geraniaceae), Fumaria muralis ssp. muralis (Papaveraceae), Hebe stricta (Plantaginaceae) and many, many others.

And, almost everywhere, a multitude of ferns, lichens, mosses, liverworts, fungi, the most amaz-ing collection of native and introduced organisms. On a relatively small surface there is such a variety and high number of species like nowhere in New Zealand. And everything amalgamated in peculiar ways, creating unique and composite eco-biotic units. On the origins of the adventives flora I would like to make two comments here: while most herbs come from Europe, Middle East or North Africa, most succulents originate from Southern Africa and Mexico; in regards to the introduction the first are usually pastoral introductions, while the latter are mostly horticultural escapes.

Off trail plant hunting is mostly hard on the shoes ... you go first and let me know!

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39 - XEROPHILIA • Special Issue, No. 5, February 2015 | ISSN 2285-3987Part 1. - III. Vegetation patterns

Geranium purpureum.Muscari armeniacum.

Myosotis sylvatica.Centranthus ruber - the red variant.

Centranthus ruber - the purple variant.Thelymitra longifolia.

Cirsium vulgare near Islington Bay Road. Fumaria muralis.

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Aira caryophylle.Myrsine australis & Geniostoma lingustrifolium

Antirrhinum majus with dense infestation of C. multicava ssp. multicava in the ackground near Rangitoto wharf

Antirrhinum braun-blanquettii near Gardiners Gap

Centaurium erythraea- the red variant.

Microsorum pustulatum ssp. pustulatum.

Hebe stricta.

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Pseudocyphellaria carpoloma, a rare foliose lichen.

Lavandula dentata east of Rangitoto wharf.

Lonicera japonica.

Osteospermum fruticosum - an almost white form.

Clematis forsteri.

Verbascum blattaria f. albiflora. Stereocaulon ramulosum.

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Astelia banksii near Rangitoto wharf

Muehlenbeckia complexa.

Oxalis incarnata.

Various succulents at Yankee Wharf.

Iris x germanica var. florentina on the path leading to the controlled mine base

Osteospermum fruticosum.

Various succulents at Yankee Wharf.

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Islington Bay wharf seen from the summit

Eco-climatic characteristicsThe climate is mild and with significant sub-tropical and oceanic influences – it does not drop below 0oC during winter, even this is an event rare enough, maybe once in 10 years, and allows for moderate hot summers. Annual mean temperatures are around 16oC. There is no meteorological station on the island but it is believed that the precipitations levels are marginally higher than in the neighbouring Auckland, possibly up to 1,200-1,300 mm/year, mainly in the cooler months and on occasion with short draught periods during the summer, especially from late December to January. Precipitations may look rather high, but considering the very poor water retention of the substrate and with the strong winds battering every now and then the area it may become even after a heavy rainfall bone-dry in a matter of days.

Apart from this, characteristic for the island is the absence of ground water and the multitude of eco-climatic niches scattered all over the island. As a result, even if only few species form the domi-

nant vegetation, there are plenty of opportunities offered for more or less resourceful species. Not to speak of the highly unusual associations between different plant species. Another factor shaping the vegetation patterns were the numerous fires on Rangitoto, during the late 19th and early 20th centu-ries, some intentional fires got out of control (e.g. climbers of the time were signalling their position by lighting a fire, this was a common practice ac-cording to Butler, 2001), some by accident (e.g. lightning) have caused a lot of trouble – especially the extensive 1887 (raging for over a week) and 1913 fires. Large bush areas were burned down to the lava fields. Currently open fires are prohibited on the island. Fires have cleared more or less large patches of vegetation favouring dynamic colonizer which otherwise would have had lower chances to become locally dominant. This explains for in-stance why kanuka, Kunzea ericoides, and manuka, Leptospermum scoparium, are very widespread on the eastern slopes and far less common on the rest of the island.

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Sand dollar, sea cookie or snapper biscuit - of the order Clypeasteroida in the flatmuds near Gardiners Gap.

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Aloe arborescens ssp. natalensis

IV. species walkthroughtitletitlesu

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After such extended passages on the natural history of Rangitoto, on its habitats and on the “other flora”, it’s about time to dive into the core of this paper: the succulent

flora! My declared intention is only to provide minimal information on the succulent plant species recorded on Rangitoto, without going into botanical details… you can find them elsewhere anyway, I will prefer to stick to my objective: to provide an updated list of species with the smallest amount of additional information. After all, most of them are well known old fashioned garden plants, or not that rare indigenous species, and therefore presenting no particular interest for the contemporary C&S enthusiast.

I’m not trying to lecture or bore to death any po-tential readers. However, particularities in regards

to the presence of those species on the island will be acknowledged, as well as references from other authors. Some of these species (if not most) have been seen by me on Rangitoto and where neces-sary additional personal remarks have been add-ed. Focus was on providing a (hopefully) complete list of succulent species (with the limitations stated in the beginning of this paper) and understanding of the habitat, its dynamics and environmental is-sues.

And, finally, I tried to include well balanced pho-tographic illustrations – helpful especially for peo-ple wanting to see this magnificent piece of nature with their own eyes. Plants will be grouped by fam-ilies, and within families in alphabetical order, for the ease of reading and retrieving of some refer-ences. And here we go…

Iconic succulent flora...

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Carpobrotus edulis (L.) L. Bolus is a common New Zealand naturalized plant and it reached Rangitoto as well, probably being cultivated at first by the early European settlers. Apparently only the yellow flowering form is present on the island. Few lose patches in Yankee Wharf and near the causeway to the neighbouring Motutapu Island. At Yankee Wharf it grows directly on the lava slabs (not exactly the ideal substrate for this plant) and stems seem to die off quite young (maybe as a result of the overheating basaltic substrate?) only to generate new shoots later on. On the contrary near Motutapu sandy soil patches are available. On Motutapu, having typically a finer sandy soil

and larger sandy beaches, there are many more patches of well-established Carpobrotus edulis growing mostly near high tide mark, in one place almost next to its natural hybrid ×Carpophyma mutabilis G.D. Rowley (see below Disphyma australe).

Carpobrotus edulis comes from South Africa, growing on coastal and inland slopes and dunes from Namaqualand in the Northern Cape through the Western Cape to the Eastern Cape, where it is often seen as a pioneer in disturbed sites, not different from New Zealand. Highly invasive in other parts of the world such as the Mediterranean region, California, etc. Ai

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Disphyma australe (W.T. Aiton) N.E. Br. ssp. australe. The traditional vernacular name is Horokaka. Sykes (1992) does not provide many details on this species: “Represented by a single specimen from Rangitoto. Although collected many years ago it probably still occurs there.” Collection date is 1920 (probably around Rangitoto wharf, although no location indicated). However, in Wilcox (2007) more information is provided (“can often be seen on shell banks adjoining the Coastal Track”) including a picture of a white flowering form dated 2005, from the southern shore. I have to admit I haven’t seen it in Rangitoto and no other information seems to be available.

However, in September 2012 I found its natu-

ral hybrid with Carpobrotus edulis, ×Carpophyma mutabilis on Motutapu, on a sandy beach close to Gardiner Gap. This hybrid is sterile (doesn’t form fruit), but still manages to backcross with D. aus-trale endangering therefore the genetic bank of our endemic ice plant. A final remark – while the Motutapu hybrid has pale pinkish flowers, sug-gesting that the pink flowering form of D. australe was involved, the picture provided in Wilcox (2007) is definitely of the white flowering form, raising few question marks. Disphyma australe ssp. australe is endemic to New Zealand and Chatham Islands. G.F. Glen lumped in the 1980s all known Disphy-ma taxons into Disphyma crassifolium (see Zimer 2012a) which in my opinion is highly questionable. Ai

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Lampranthus sp. is known only from a cultivation relic that couldn’t be even properly identified by L.M. Cranwell who did the collection back in 1941 (?), according to Sykes (1992). Wilcox (2007) does not even mention this taxon, and therefore Sykes’ account becomes somewhat doubtful. Possibly it became naturally extinct on the island. Lampranthus comes from South Africa and is very popular in cultivation in New Zealand. Ai

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Tetragonia implexicoma (Miq.) Hook f. – is also present in Rangitoto at Wreck Bay, on the northern shore, but its stems are succulent only in juvenile and young shoots (in adult plants at least) and is distinguished by its reddish colour of the old, non-succulent stems and, sometimes, of the leaves. Native to New Zealand, Australia, Norfolk and Lord Howe islands.

None of the Tetragonia species is, however, a typical succulent plant and didn’t really look out for it while in the field. I vaguely remember seeing possibly T. implexicoma at Wreck Bay or Boulder Bay, but I have no notes or pictures.

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Tetragonia tetragonioides (Pallas) Kuntze was known for a long time only from the 1889 record of T.F. Cheeseman but was later retrieved at Flax Point and, as in Wilcox (2007) is stated grows even “more luxuriantly” at the adjoining black-backed gull colony, with other 25 other plant species, probably because of the freely available fertilizer. (In return the gulls harvest vegetation to line out their nests). T. tetragonioides is a common beach plant, endemic to New Zealand, used traditionally for food (vernacular name is New Zealand spinach). Typically seeds are dispersed by sea water.d. Ai

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Tetragonia trigyna Banks & Sol. ex Hook.f. is only known from a historic collection in 1932 (Sykes, 1992) when a sterile speci-men was recorded and collected, however, with uncertain specific identity. Some au-thorities include T. trigyna in – Tetragonia implexicoma (Miq.) Hook f.

trygina (see page 51). Both Tetragonia tetragonioides and Tetragonia trigyna are relatively common in other Hauraki Gulf islands but almost lacking from Rangi-toto, and both have trailing succulent stems and semi-succulent leaves. And, both are endemic to New Zealand.

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Sarcocornia quinqueflora (Ung. Sternb.) A.J. Scott ssp. quinqueflora is a typical shore line and salt marsh species, a very common and wide spread halophyte in New Zealand (however, it lacks com-pletely from the West Coast of the South Island). It was formerly classified as Salicornia. There are several species worldwide known in Europe under generic names such as Marsh Samphire (as it was used as subsistence food or pickled for many hundreds of years) or Glasswort (be-ing used for glass production in early years). It is a very interesting plant, seemingly dying off in winter, only to revive in summer (the dead skin peels revealing fresh green new growth).

Locally very abundant in Rangitoto, growing near high tide line in sand and silt accumula-tions, on temporarily submerged coastal lava blocks, on lava slabs in the splash zone or on oc-casion on higher ground, but still in the mist. It is completely missing in some parts of the island, leaving some unexplained gaps. S. quinqueflora ssp. quinqueflora is native to New Zealand and Australia, while a second variety, var. tasmanica, grows naturally only in Australia. Typically, in New Zealand this is a shoreline species, while is Australia several inland populations are known.

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Suaeda novae-zelandiae Allan is known to grow in Rangitoto since the 1930s (Sykes, 1992). “Ran-gitoto Wharf. Scattered plants grow in the salt-wort community in the bay near the landing jet-ty.” I have seen it in the same location, a dense strip on somewhat higher ground doubling S. quinqueflora placed directly in the high tide area. Both species are often associated, although at least in Rangitoto S. novae-zelandiae is not very common. Not a spectacular plant, but a truly halophytic survivor. Forms twisted low thickets with stems rising on occasion up to 30-40 cm. En-demic to New Zealand, where it is very common especially in the South Island.

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Alocasia brisbanensis (Bailey) Domin (= Alocasia macrorrhizos (L.) G. Don var. brisbanensis F.M. Bailey) – well known as Elephant’s ear – was only sparsely found at Wilsons Park probably as a remnant of the intended botanic garden. Only few plants, as Sykes (1992) states. Adventive in few other places in New Zealand, but really in-vasive and dominating large vegetation areas only in Raoul Island (Kermadec) (Sykes, 1992). According to Wilcox (2007) and Witherspoon & Witherspoon (2002) currently eradicated from Rangitoto. It comes from Australia (Queensland).

Colocasia esculenta (L.) Schott is a tropical plant grown primarily for its edible corms (known as taro), and only later on becoming an ornamen-tal plant. Sykes (1992): “Wilsons Park at base of crater cone. A few patches only.” Apparently an-other relict of the intended botanic garden. This species is thought to have been originally native to the lowland wetlands of Malaysia, but was intensively cultivated since ancient times and spread to India, Ancient Greece and Rome, and further in the civilized world. It is widely natural-ized wherever it has been cultivated..

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Alocasia brisbanensis, growing at Dorrigo National Park, Australia - photo by C. Goodwin, ex Wikipedia

Colocasia esculenta

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Zantedeschia aethiopica (L.) Sprengel is spread across the island in small groups (cultivation relics) near baches or former gardens. It didn’t spread rhizomatous to form uncontrollable thickets in Rangitoto as this is a moisture loving plant and thrives especially near gullies or rivers, sometimes in periodically flooded areas, but this is exactly what the harsh environment of the island can’t offer. However, here and there, small groups re-sisted the challenge of the time.

Sykes (1992) places the plant in Wilsons Park and western parts of Rangitoto, however, I have seen it only in the eastern parts, near Islington, garden relicts in somewhat sheltered and possibly more humid position, in the backyard of a demolished bach. (Nearby several piles of old empty bottles reminiscent of noisy parties). This species comes from Lesotho, Swaziland and South Africa. Ar

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Agave americana L. – the original Century plant, thought to flower once in 100 years - is present almost everywhere near former settlements on Rangitoto, at Gardiners Gap, near the baches around Islington wharf, Yankee Wharf, on the trail to the Controlled Mine Base, and almost the en-tire southern coast… however, DOC makes a big point in thoroughly controlling this species. All ma-ture specimens have been removed, sometimes in a disputable manner, for at least 15 years there were no more flowering specimens seen here. However, not seed dispersal is the problem. A. americana was intensively planted on the island

as it was and still is one of the most common and loved succulent plant in New Zealand gardens, be-ing tough as old boots and with little to no need of maintenance. By removing the old flower sized plants the problem hasn’t been solved. Deep down in crevices and fissures of the lava slabs there are myriads of rhizomes carrying on and emerging again and again as new plants. An almost impos-sible task and on the long term an expensive ex-ercise. The Agave plants thrive on Rangitoto – a perfect substrate and acceptable climate - and are possibly in their many hundreds, including all the small suckers. As

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Initially I was trying to study the development of the few more or less densely populated colo-nies, but soon I realized this was pointless as every year most of the bigger plants were checked by DOC. The specimens on Rangitoto are also quite different from most of the plants you can see in contemporary Auckland gardens – mainly slender specimens or variegated forms of relatively recent horticultural origins; as there is a presence of Aga-ve americana in Hauraki Gulf and Great Auckland area of over 140 years we possibly deal here with original, unaltered stock.

However, there are only few varieties, forms or cultivars that have spread in cultivation and even-tually have been naturalized worldwide, this com-plex is far more intricate.

A. americana comes from sub-tropical to warm-temperate regions of Mexico and has managed to escape from cultivation in many regions of Medi-terranean Europe, South Africa, Australia, New Zealand and many Pacific Islands – such as Lord Howe Island, Pagan Island, Cook Islands, Galápa-

gos, Fiji, French Polynesia Islands, Tahiti, and many others, usually not putting pressure on native habitats, but on occasion becoming aggressive in-vaders – as it happened in Palau, Ogasawara Is-lands (Japan), or New Caledonia. Extremely hard to control, not because of the many thousands of seeds scattered by a flowering plant, but because the rhizomes spreading through the cracks, gaps and crevices of the lava fields… virtually impossi-ble to eradicate if you have to deal with hundreds of plants at a time. Larger specimens are removed or literally butchered at site, for at least 15 years no A. americana has reached flowering age on Ran-gitoto.

Agave americana L. ‘Variegata’ is mentioned by Sykes (1992) as forming “occasionally large clumps growing as relicts of cultivation” which I haven’t seen and possibly have been already wiped out. There are several variegated forms, but by far A. americana ‘Marginata’ is the most common in cultivation in New Zealand and very probably this was seen by W.R. Sykes. As

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Agave americana 'Marginata' (aka 'Variegata') - cultivated

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Yucca gloriosa var. tristis Carrière (mostly re-ferred as Yucca recurvifolia Salisb. or Yucca glo-riosa var. recurvifolia Engelm.) is mentioned by Sykes (1992) growing as cultivation relicts near garden sites in Islington and Rangitoto wharf.

I have seen in Rangitoto only the occasional regrowth, not massive plants (as an adult it has a shrubby to tree like habit and grows up to 2-3 metres high). It comes from the south-eastern parts of the USA.

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Ornithogalum caudatum (Aiton) Maire is men-tioned in Wilcox (2007) as O. longibracteatum Jac-quin (sometimes spelled O. longebracteatum – which is wrong). In later years it was reclassi-fied as Albuca bracteata (Thunb.) J. C. Manning & Goldblatt, which seems to be the currently ac-cepted name, although less in use by amateurs.

This is a bulbous plant growing surprisingly well on the lava fields – you would expect it rather to thrive in deeper and more porous substrate.. I have seen dozens of mature plants, some with the bulb nearly 8 cm across (it can reach up to 10-12 cm), near the track between Yankee Wharf and the Controlled Mine Base.

O. caudatum is a classic cryptophytic succulent (with bulb-like layered succulent stem) having strap like slightly succulent strap like leaves which can reach up to 80-100 cm length. Characteristic for this species are the small bulbils growing from the main bulb which can start a new plant when detached, rooting readily and starting to grow when moisture available. It seems to work well for this species in Rangitoto, as many tiny plants could be seen around the larger mother-plants. In my experience it is a bit more difficult and slow to grow from seed, planting bulbils is like a game...

Vernacular names are False Sea Onion (and it looks indeed like an oversized onion) or, quite un-derstandable, Pregnant Onion. Curious little plant which I have no idea how could establish so well quite far from the former dwellings. It comes from southern and tropical eastern Africa.

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Senecio angulatus L.f. There are at least 13 Sene-cio species confirmed on the island (Wilcox, 2007), some adventive, most of them native, but only S. angulatus (common name Cape ivy) can be con-sidered a succulent plant, having succulent stems and semi-succulent leaves from juvenile to adult status.

Sykes (1992) mentions only few patches at Is-lington, around old baches, struggling to spread vegetatively. ”It may not form viable seed as no seedlings or young plants were seen.”

I have seen only few decrepit plants I thought were not really worth photographing. Although

it grows preferably on dry coastal situations it seems that Rangitoto is a bit too much of an ask and this species needs a bit of constant moisture supply throughout the year and does not very well on hot basaltic lava slabs, with little to no organic accumulations. In other locations observed by me (especially Napier) S. angulatus is able to form lush stands, smothering various plants and even tough invasive species such as Opuntia monacantha. Senecio species are self-pollinating and propagate easily by seed dispersal by wind so Sykes’ state-ment has to be put into perspective. Senecio angu-latus comes from South Africa. As

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Impatiens sodenii Engl. (below) used to be a highly appreciated or-namental plant flow-ering almost all year round (one vernacular is shrub balsam) and cultivation relics are seen at old house sites, around old baches or abandoned gardens in Islington and Rangitoto wharf.

Sykes (1992) main-tains it is a prolific seed-er, but doesn’t seem to spread too much, apart from few groups. The species forms shrubby plants with succulent stems.

It comes from Kenia and Tanzania.

Impatiens walleriana Hook f. (left) is a similar species, only with less succulent stems (if this is relevant for this pa-per).

It is native to East Af-rica, from Kenia to Mo-zambique.

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Cakile maritima Scop. ssp. maritima is a moder-ate halophyte shrubby annual plant with succulent stems and leaves. Fruits are ripening in summer and seeds germinate in winter, when most of the parent plants are dead by now. This species typi-cally has an asynchronous germination, forming a seed bank lasting for several years (over three years from the same seed batch) assuring propa-gation even in adverse conditions. Seeds are dis-persed locally by wind while long range dispersal

occurs with the help of sea waves and currents. It is a typical beach and sand dune species; this is ac-tually the only suitable habitat type. Rangitoto of-fers only one adequate spot, Whites Beach, where C. maritima occurs, along with other characteristic sea shore species. It comes from Europe, but be-came adventive in several parts of the world, and even a noxious weed in North America, on both coasts. Several varieties and species have natural-ly a mostly northern hemisphere distribution.

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eOpuntia monacantha (Willd.) Haw. The only ac-count on the presence of this species on the is-land is Natural History of Rangitoto Island (Wilcox, 2007) where it is merely listed in the species sum-mary (on page 109), and not even in the index. I have no other source, and I don’t know based on what account has been included here. I haven’t seen it on the island, nor is it mentioned in Sykes (1992). However, I am pretty sure that at some stage this species must have been planted here, maybe in Wilsons Park, the intended botanical garden, or possibly near baches, as it used to be a common cactus in the gardens of the early to mid-20th century.

Opuntia monacantha is native to Argentina, Bra-zil, Paraguay and Uruguay, but has been widely introduced and naturalized in almost all tropical and subtropical regions, from Florida to tropical

Africa, to South Africa, southeast Asia, Australia, New Zealand and some of the Pacific Islands, and I think there must be some other places too. The worst infestations have occurred in Australia and South Africa. It is also worthwhile mentioning that Opuntia monacantha was first recorded in China as early as 1625. Opuntia monacantha is probably the most common opuntioid in cultivation in New Zea-land, everyone seem to know it, have seen or had one, and so on. There is nothing special about this plant, widespread and almost a pest even in its own habitat. It is actually a poorly studied complex of plants ranging from multi-branched shrubs to tall trunk forming arborescent types. Prolific flow-erer, it doesn’t form seed but easily propagates locally from detached pads and rooting fruits. Long range propagation occurs only by intentional planting.

Opuntia monacantha, here severe infestation at Tutukaka coast.Below: Cultivated plants.

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Tradescantia cerinthoides Kunth is naturally much rarer compared to Trandescantia fluminensis and currently eradicated from Rangitoto (Wilcox, 2007). It is a typical weedy cultivation escape (hor-ticultural waste dumped illegally). “Does well on dry rock faces especially on lava.”

Apparently New Zealand plants do not form seed (New Zealand Plant Conservation Network) but easily propagates from detached stem frag-ments. It has long trailing succulent stems and semi-succulent leaves, and is distinguished from the more common and invasive Trandescantia flu-minensis by its colourful flowers. Sykes (1992) is mentioning it from Islington. “One small patch in a lava crevice on the margin of scrub near an old house site. (…) Tradescantia cerinthoides has usu-ally been treated as T. blossfeldiana Mildbr. in New Zealand and elsewhere. This is apparently the first report of it being adventive here.” It comes from

South America (Brazil, Argentina).Tradescantia fluminensis Vell. (photos) is cur-

rently eradicated (Wilcox, 2007) from Rangitoto, which is a real achievement. Known as the Wan-dering Jew, Wandering Willie or Wandering Gyp-sy, this species thrives in woodland openings, on moderately moist to almost swampy ground, covering with its long trailing succulent stems and semi-succulent leaves the ground, smothering na-tive vegetation and killing their seedlings.

In time, it can form large monotypic vegetation patches, causing severe infestations in only few years if unchecked.

A real concern where is sets foot. It is resistant to chemical control being helped by the glossy leaves and smooth stems. It also regenerates form the smallest stem fragment left behind. Dark green leaves, white flowers. This species comes also from South America.

Photo & detail: Tradescantia fluminensis, here a severe infestation at Eastern Beach.Above Left: Tradescantia cerinthoides, flowers - photo Isabella C..Above right: Tradescantia fluminensis, flowers.

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CrassulaceaeThis plant family includes several succulent spe-cies very well represented in Rangitoto. As a mat-ter of fact, it is the biggest group, not only judging by the number of species, but also by the impact on the local flora.

There’s no better place to start, but with the most confusing plant group: various Aeonium spp. & Ae-onium hybrids (Macaronesia). The botanical litera-ture mostly refers true species, but as we speak there are very little specimens on the island which could pass as the true species. Huge amounts of hybrid swarms are everywhere; as a matter of fact it becomes very difficult to draw a line as there is a continuum of forms. However, botanists named certain species in their works, and therefore I have to go this path as well.

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Aeonium x floribundum A. Berger. (A. caespitosum x A. spathulatum) Sykes (1992) mentions three col-lections made between 1987 and 1991 in Islington, on Rangitoto’s eastern coast. Fact is that 20 odd years later I have not seen this plant in Islington, but in several occasions and in different sites in the southern parts of Rangitoto, west of Rangi-toto wharf, not intermingling with other Aeonium species. Rather less common in fact than other Aeonium species. Synonym is Aeonium x hybridum (Haw.) G.D. Rowley, although I’m not very sure it is the same plant. Some throw also Aeonium x bar-batum in the mix. According to International Cras-sulaceae Network “the name Aeonium x barbatum for this hybrid is not correct because A. barbatum is considered a synonym of A. simsii [a synonym

of A. caespitosum], so any later hybrid cannot use that name.” Personally I find Aeonium x barbatum visually quite different from Aeonium x floribundum and, more, even if the name Aeonium x hybridum might have precedence I prefer not to use it, but use instead the name referred in New Zealand botanical lit-erature. The main reason is that, even if purely from botanical point of view they might be all the same; these are all hybrid entities… possibly spontaneous or maybe selected, however, usually specimens we know are at the end of a long and separate more likely clonal than sexual propaga-tion line. We are talking about distinct “cultivated products”, even if they all might share the same parentage.

Aeonium x floribundum, in early spring near Rangitoto wharf.Above: Aeonium x floribundum, west of Rangitoto wharf in high summer

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Aeonium arboreum (L.) Webb et Berth. var. ar-boreum × Aeonium undulatum Webb et Berth. Heenan et al. (2008) reports a 1987 collection by W.R. Sykes in Rangitoto. In my opinion this is an even more dubious identification and is yet con-tradicting a more credible Sykes’ 1992 statement. Heenan et al (2008) refers Sykes (2004) as the first record, however, reading Sykes’s 2004 paper I couldn’t find any reference of Rangitoto or the 1987 collection in the text. This hybrid probably exists somewhere out in the wild in New Zealand, but very probably not in Rangitoto.

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Aeonium cf. ciliatum – probably a plant of hybrid origin, does not match exactly the description of the original species. Given (1984) believes that this plant may be a hybrid of A. ciliatum with A. urbicum (C.A. Smith) Webb & Berthelot. He outlines also the main differences: “This differs from A. ciliatum in its entirely green leaves (red margined in A. cili-atum), greenish flowers (reddish in A. ciliatum), and somewhat apiculate leaf tips (almost blunt in A. ciliatum).” Its presence in Rangitoto is officially un-confirmed and could be another misidentification; however, I have seen few small seedlings which could be a match.

Aeonium cf. ciliatum, near Islington Baysu

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Aeonium haworthii, near the Controlled Mine Base.Detail and below: Aeonium haworthii at Islington Bay.

Aeonium haworthii Webb & Berth. In later years, mostly hybrid plants, barely any which could pass as the true species. The plants seen here by me where much reduced and branching sparingly (not forming their characteristic dome of rosettes) but nevertheless some splendid specimens were scat-tered on the lava blocks. Used to be relatively com-mon in Islington and Yankee Wharf (east) before early 2008, but after a massive purge in late 2008 or early 2009, plants that might pass as the true species became extremely rare.

In other parts of New Zealand where extensive or scattered populations of A. haworthii exist, if left alone, it can form dense monotypic stands, some of them of appreciable age, spreading seed and maintaining the true line. However, in Rangitoto, especially during the last 10-15 years, when exotics became more often and more thoroughly checked by the Department of Conservation (DOC), fact is that the true species almost disappeared being re-placed, in time, by hybrids with possibly multiple parentage. This is true for all Aeonium species.

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Aeonium undulatum Webb & Berth. Few isolated plants were described as growing close to the high tide line. First collec-tion from Rangitoto is dated 1986 (W. R. Sykes). This species used to be very common in Is-lington and Yankee Wharf, in the east, and less around Ran-gitoto wharf, in the south, but as with A. haworthii, it became extremely rare after 2009.

Aeonium undulatum, in high summer, Islington Bay colony.Above: Aeonium undulatum, in spring.Detail above left: Aeonium undulatum, a somewhat greener form, in high summer, Islington Bay colony.Detail above right: Aeonium undulatum, in high summer, Islington Bay colony.

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Most of the plants are definitely hybrids, most of them apparently A. undulatum x A. haworthii having a more or less transitional aspect. This hy-brid seems to be very abundant, especially along the coastal track between Islington Bay wharf and Yankee Wharf. From the many forms I have seen and collected in 2008 there is a plant later described as Aeonium ‘Rangitoto’ E. Zimer (Zimer, 2010b; Zimer, 2012), which I first thought it could be the above mentioned hybrid backcrossed to A. haworthii.

However, in time, cultivated F2 and F3 genera-tions proved to become more and more similar to Aeonium ‘Rangitoto’ to the point that the difference becomes very difficult to recognize (and therefore I had to tag all my plants). In contrast to the theory advanced initially I seriously consider that Aeonium ‘Rangitoto’ is nothing else but F2 or F3 generations of the initial A. undulatum x A. haworthii hybrid and that the change in appearance is due to the ge-netic dominance of A. haworthii.

Another interesting aspect is revealed by Sykes (1992) in his comment on A. undulatum: “One plant from Rangitoto part of which was grown to flow-ering at Auckland University has whitish or cream flowers instead of the usual golden ones of this species”. This could have been the plant I named Aeonium ‘Rangitoto’ as lush growth in moist and shaded situations can resemble A. undulatum in-deed. However, its flowers are pretty much A. ha-worthii like – and this is exactly what W.R. Sykes noticed.

In late 2008 or very early 2009 DOC has cleared most of the larger Aeonium plants in Islington and Yankee Wharf. Since then the Aeonium populations have regenerated mostly from seedlings and got to flowering size in time. However, the vast majority of plants are hybrids so we can hardly speak now of the true species growing there. There still are a few plants around that could indulgently pass as A. undulatum, but definitely not even a handful of A. haworthii. Cr

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Aeonium undulatum x A. haworthii, in high summer, from the Islington Bay colony.

Aeonium undulatum x A. haworthii, in high summer, from the Islington Bay colony.

Aeonium undulatum x A. haworthii (left) and A. undulatum (right), Islington Bay colony.

Aeonium 'Rangitoto', cultivated plant.

Aeonium 'Rangitoto' in habitat in 2008. Aeonium havorthii and Aeonium. 'Rangitoto', cultivated plants

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Crassula coccinea L. is widespread and relatively abundant in Isling-ton, Yankee Wharf and Rangitoto wharf, but without forming massive stands, only specimens scattered here and there. It has spectacular big crimson flowers in high summer. Loves lava fields and rock rubble, so no wonder it thrives here. Used to be one of the most popular gar-den plants in the early 20th century and still is quite often seen in old fashioned cottage gardens. Spectacular during flowering! I don’t know if Rangitoto plants produce seed, however, this species is tough as old boots… endures heat and drought in summer and endless rainy days in winter. Even if it fails, it rarely dies off completely as new shoots emerge when the time is right from seemingly dead plants. It comes from South Africa (its main distribution centre being in Table Mountains).

Crassula coccinea. Crassula coccinea, flowers, Yankee Wharf.

Crassula coccinea, with Cladonia confusa.

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Crassula decumbens Thunb. Seems to be a very common cultivation relict in New Zealand, how-ever, I failed to see it in Rangitoto. Sykes (1992): “Rangitoto wharf. Only observed in and west of this settlement where it grows on open lava fields near coastal tracks. It may have escaped notice elsewhere because of its small size and rather ephemeral habit”. It comes from Southern Africa and Australia.

Photo by Harry Rose in unknown location.

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Crassula multicava Lemaire ssp. multicava is probably next to various Aeoniums the most wide-spread succulent pest in Rangitoto. As it is very versatile it grows everywhere, taking any available spot from full sun on the hot lava slabs, to mois-ture and shade. In the open it is probably not very invasive, but in relatively sheltered situations it is able to replace the entire ground cover vegetation on large patches in a matter of years.

Crassula multicava, with plantlets at Yankee Wharf.Detail: Crassula multicava, flowering plant near Islington Bay.

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It seems that New Zealand plants do not form seed, but instead this species forms tiny plantlets in the flower axiles and this supports its invasive be-haviour. The myriads of cracks, fissures and small crevices of the lava fields, offering shelter and ac-cumulating organic matter and moisture, are ideal for the small plantlets to establish. This species is very easy to distinguish from similar species (Cras-sula streyi or Crassula sarmentosa var. integrifolia) by the marginal hydathodes scattered on both leaf surfaces. C. multicava used to be another garden favourite of the post-Victorian era and even if it was officially recorded only in 1959, it could have become an adventive plant much earlier. It comes from South Africa. Crassula multicava is unfortu-nately one of the very few succulent pests that have not been contained only along the coastline of Rangitoto but penetrated the interior of the is-

land. I have seen few plants and literally hundreds of small plantlets scattered in a place that looks to have been used as a temporary storage halfway of the southern summit track. I’m monitoring this spot since 2009 and C. multicava seems to become more and more established here. Another place is next to Wilsons Park, beneath the crater rim. Again, few larger plants and several scattered plantlets. As some of the plants were growing next to stored barrels containing weed control chemicals, so I guess that the infestation has been produced by DOC workers. In October 2014 I have noticed a couple more infestation points on the southern summit track, so it seems to advance steadily and unperturbed towards the interior. Fortunately the infestation sources are still much localized; it’s only up to DOC to do something about while still a relatively easy job.

Crassula multicava, with Cladonia confusa at Yankee Wharf

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Crassula orbicularis L. Several patches of plants persisting in the proximity of an abandoned quar-ry pit in Islington were reported by Sykes, 2005 (“The plants were growing in fine scoria and were evidently spreading by detachment of rosettes. This readily happens because of the fragility of the thread-like runners.”) and by Heenan et al (2008). Being considered potentially highly invasive all plants were removed and in 2006 no other plants were found when the site was revisited. In my opin-ion, as it is very frost tender, this species had little chances to establish large populations anyway. It comes from South Africa.

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ulaCrassula pubescens ssp. radicans (Haw.) Toelken. I

stumbled across this species where I expected the least, far from the southern human settlements, West of Rangitoto wharf, at Flax Point relatively close to the black back gull (Larus dominicanus) breeding colony, out in the open lava fields, but still finding shelter in the numerous crevices. This contradicts somewhat Heenan et al (2008) who suggested localized dispersal: “Plants grow read-ily from detached stems and leaves (…) gathered from a range of habitats and situations, usually near garden plants”, but it definitely wasn’t the case here. I have no idea how it could have ended up here, unless dispersed by birds. This is another South African species.

Crassula pubescens ssp. radicans, at Flax Point.su

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Crassula sarmentosa Har-vey was known to have es-caped in nature since 1989 in Auckland, but P. J. de Lange has collected it only in 1995 from a slipway in Rangitoto, growing as a garden discard on scoria blocks. The finding was published in Heenan et al, 1999. Apparently still very rare, Crassula sarmentosa is not considered a threat and is not included in any current vegetation control program. It comes from South Africa.

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Crassula sarmentosa, cultivated plants.Detail left: Crassula sarmentosa,with completely variegated shoot.

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Crassula sieberiana ssp. sieberiana, here at Bethells Beach.Detail above: Crassula sieberiana ssp. sieberiana, Bethells Beach

Crassula sieberiana (Schul-tes et Schultes f.) Druce ssp. sieberiana is a tiny succulent short lived perennial or even annual herb, depending on the circumstances. Easy to overlook. Reported from Ran-gitoto wharf in the south and around the main crater rim. This subspecies is native to New Zealand and Australia, while two other subspecies (C. sieberiana ssp. tetramera and C. sieberiana ssp. rubinea) occur only in Australia.

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Crassula tetragona ssp. robusta (Toelken) Toelk-en is reported from Islington and Rangitoto wharf (Sykes, 1992), however, in my experience it is most-ly common in Yankee Wharf, south of Islington wharf and is somewhat less obvious in other parts of the island. Populations are pretty much local-ized but contain typically a large number of plants growing close to each other, abundantly flower-ing in spring. I have seen only very few seedlings but vegetative propagation is easy. The long and thin stems are quite brittle and break during gusts or even under their own weight (especially when flowering), being swept by winds and rooting ef-fortlessly where they land. Vegetative propagation is most effective for this volcanic rock rubble lov-ing species. It comes from South Africa. Cr

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Echeveria multicaulis Rose is known from a single W.R. Sykes 1989 collection in Rangitoto and was first mentioned by the same in 1992. The speci-men was collected from lava rubble near a de-molished house site in Islington and was one on the very few plants present on site. I spent many hours starting with my January 2008 trip searching for this plant, more than for any other plants, but to no avail; luckily in September 2011 I chose to take a small shortcut through the bush and here it was in a small glade, just in front of me, only cou-ple of metres from the track, but otherwise hid-den. Tall growing, to 30-40 cm, and having usually small tight rosettes coloured from dark green to

olive to copper red-brownish colours especially in the apical half (and hence the common name cop-per rose), depending on the light conditions, with red flowers. However, this particular group of plants (one taller, a couple of smaller ones appar-ently originating from the main specimen) wasn’t really close to a demolished bach site. It doesn’t have a high invasive potential, on the contrary, so it is just a limited exotic addition to Rangitoto’s var-ied flora. Echeveria multicaulis comes from Mexico. Cr

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Echeveria secunda W.B. Booth was seen and collected, according to Sykes (1992), from “Is-lington. A few small non flowering plants only growing around an old house site.” Sykes’ ear-liest collection is dated 1972, the latest 1989. Flora of New Zealand Volume IV (1988) is also mentioning this species in Rangitoto - C. J. Webb & al. (1988) – questioning, however, the name and suggesting that collected material could very likely belong to one of its subspecies very common in cultivation. A completely sen-sible judgement. However, their short state-ment is stunning and (for me at least) quite un-intelligible in another aspect: “Many cultivated plants correspond to var. elegans (Baker) Otto, which has larger and more glaucous leaves, but it is impossible to ascertain whether or not any dried specimens represent this var.” As far as I am concerned – there is no Echeveria secunda var. elegans (Baker) Otto! I wonder if the authors meant the relatively similar Echeve-ria stolonifera (Baker) Otto. Or did they mean Echeveria elegans Rose which, even if not a va-riety of Echeveria secunda, has indeed “larger and more glaucous leaves”? Echeveria elegans would be a very good candidate considering both aspect and extreme popularity among gardeners especially few decades back. I would also consider Echeveria secunda Booth ex Lindl. var. glauca as a good candidate (it has “more glaucous leaves” indeed, although not larger), which seems to be the more common variety in Auckland gardens even today.

Echeveria secunda f. glauca, cultivated plant.

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It is easy to propagate from cuttings, leaves and bracts in cultivation, but rather amorphous and unable of unassisted propagation. I haven’t seen it and it is hard to believe it’s still out there. Very popular in New Zealand gardens (and especially represented by var. glauca as mentioned above). It is one of the species which became highly suc-cessful in cultivation, and therefore less and less interesting for serious hobbyists, to the extent that no-one is interested anymore of the remarka-ble variability shown in habitat. One extra problem with this species (and generally with most similar Echeverias) is that dried herbarium specimens are mostly useless for a precise identification Late Ron, if not done properly when the live genetic material was collected. My point is – under the E. secunda umbrella might hide quite different spe-cies, cultivars and hybrids. This is another popular Mexican Echeveria species.

Echeveria elegans, cultivated plant.

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Echeveria setosa Rose & J. Purpus. Recorded by Sykes (1992) as “two young plants” and acknowl-edged by the same in 2004 as a misidentification of Echeveria ‘Set-Oliver’

Echeveria ‘Set-Oliver’ Walther has an uncertain status. There is at least one formally unidentified collection (but presumably Echeveria ‘Set-Oliver’) dating back to the early ‘70s made by A.E. Esler. More, Sykes (2004) is dismissing his 1992 claim as being most likely a misidentification (“almost cer-tainly wrong”). I am pretty confident in saying that it has been cultivated here – it was extremely pop-ular in Auckland gardens few decades ago, why wouldn’t it have been in the rock gardens nearby the holiday baches of the same Aucklanders? It does not set viable seed, so we have to look at vegetative propagation. It propagates readily from

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cuttings; the only problem I have found is that some organs able to assure propagation more likely in unassisted situations (i.e. detached leaves or bracts) are somewhat prone to fungal attacks and even in controlled cultivation I couldn’t get the same good results as with other similar plants, es-pecially in wet weather even if sheltered (due to increased relative air humidity). I think that Ech-everia ‘Set-Oliver’ could have escaped cultivation in Rangitoto or carry on as a cultivation relict for some time, but I give the plant low survival chances considering the limited propagation means avail-able and the thorough DOC vegetation checks per-formed especially in the last 10-20 years. It is not exactly persistent either as older plants become in my experience less and less energetic in time. It is a classic Echeveria setosa x Echeveria harmsii hybrid created by Victor Reiter Jr. in the USA in 1932.

Echeveria 'Set-Oliver', cultivated plant.

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Kalanchoe delagoensis Eckl. & Zeyh. is usually mentioned as Bryophyl-lum delagoense (Eckl. & Zeyh.) Schinz in New Zealand botanical records. Sykes (1992) mentions again Isling-ton. I haven’t seen it there but along the path to the Controlled Mine Base were scattered literally thousands of plants and, less numerous, few kilometres away forming a small but relatively steady population seem-ingly spreading out of the aban-doned gardens of two baches west of Rangitoto wharf. Extremely tough, heat and draught resistant, it is eas-ily self-propagating due to the small plantlets in the notches at the mar-gin of the leaf blade. A pest in culti-vation, especially in greenhouses, as it tends to spread everywhere. It has the habit here to form packed, niche oriented populations. It comes from tropical S-E Africa.

Kalachoe delagoensis, it is easily self-propagating due to the small plantlets in the notches at the margin of the leaf blade.

Kalachoe delagoensis, west of Rangitoto wharf.

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Kalanchoe ‘Houghtonii’ D.B. Ward (usu-ally mentioned as Bryophyllum ‘Houghto-nii’ (D.B. Ward) P.I. Forst in New Zealand botanical records). Yankee Wharf locally abundant, along the track, and also on the huge the concrete platform at the Controlled Mine Base, heavily infested, where it grows in the open from all pos-sible cracks and fissures. Was misiden-tified in early records (notably Webb et al, 1988) as Kalanchoe delagoensis. It ap-pears to be a spontaneous greenhouse hybrid Kalanchoe daigremontiana x K. tubiflora from the early 20th century, in the United States. Cr

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Kalachoe ' Houghtonii' near the Controlled Mine Base.su

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Kalanchoe pinnata (Lam.) Pers. has been originally recorded as Bryophyllum pinnatum by W.R. Sykes in 1977 in Kermadec Islands, and later on in Rangitoto and other Hauraki Gulf islands. The air plant by its vernacular name comes from tropical Asia and pre-fers “open scrub on sandy soil, rock crevices and out-crops.” (D.R. Given, 1984). These succulents were once very popular house plants and are native to Madagas-car. I haven’t seen any, I assume this species occupies only localized patches kept under control by DOC. Al-though it is the “Mother of Thousands” type of plant it doesn’t seem to be an aggressive colonizer as the two species mentioned above.

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Kalanchoe pubescens Baker is mentioned by Sykes (1992) as Bryo-phyllum aliciae (Raym.-Hamet) A. Berger growing in Islington “on an old house site where it persists as a relic of cultivation”. Not known to be naturalized or adventive anywhere else in New Zealand (not mentioned in Howell et al, 2006). I haven’t seen it, in Rangitoto or anywhere else. This species comes from Madagascar as well.

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Sedum acre L. can be eas-ily confused for S. album, more common in Rangi-toto, when not in flower. S. acre has, on the con-trary, yellow flowers like most sedums, scale like fat and packed leaves and a more upright stand when not in flower. It was recorded on Rangitoto by Given (1984) and sub-sequently mentioned in Wilcox (2007), but not by Webb et al (1988) refer-ring only vaguely Auck-land, and completely o-mitted by Sykes (1992).

I haven’t seen it and, as it flowers in late spring to early summer, I couldn’t have confused it for Sedum album if I saw it. It may have only a much localized distribution, like many other species on Rangitoto. In absence of more precise information on its whereabouts, I leave it to chance to see it one day. Very easy to overlook anyway. Naturalized in several areas in New Zealand, “Stonecrop is the commonest Sedum sp. wild in N.Z. and in suitable habitats can carpet the ground.” (Given, 1984). This species comes from Europe, Western Asia and North Africa and was known since antiquity for it acrid taste (one of its common names is Biting stonecrop) and is naturalized in several parts of the world, including Greenland!

Sedum acre, here growing on a hillside near Cromwell - Photo by André Richard Chalmers ex Wikipedia.

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Sedum album L. Sykes (1992) states: “Islington and Rangitoto Wharf. Near houses and beside the tracks near the settlements sometimes form-ing large mats several metres across.” Webb et al (1988): “(…) Auckland, especially Rangitoto Id (…).” I have seen it mainly near Islington and Yankee Wharf in the east, and west of Rangitoto wharf, with only a couple of exceptions in the proximity of abandoned baches. While nice apple green in early spring, S. album gets beautiful bronze col-ours in high summer, when exposed to intense sun and deprived of water. Flowers are white, flowering stems are terminal, but also numerous new shoots are appearing. It almost disappears in late summer, only to recover again. The leaves are alternate, fleshy and nearly cylindrical with a blunt, rounded tip. This species comes from Europe, Western Asia and North Africa and knows sever-al distinct varieties and forms. Only few of them seem to be present and adventive in New Zealand. However, it is one of the alpine plants seemingly preferring the cooler climate of the South Island.

Sedum album, cultivated plant.Detail right: Sedum album, plant in Rangitoto.

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Sedum forsterianum C. A. Smith was recorded by Webb et al (1988) in “Lit-tle Barrier Id (N. Auckland), Rangitoto Id and several localities in Auckland City” (as S. forsteranum – sic!), repeated in 1989 (this time with the correct spelling), while in Wilcox (2007) is also listed this species, without any comment. However, Sykes (1992) considers this a misidentification when writing about S. mexicanum: “This is the plant recorded from Rangitoto and some other places in the region as Sedum forsterianum Smith

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(Webb et al. 1988) but the latter species apparently is not wild in New Zealand.” S. forsteri-anum has been also confused for S. reflexum (or vice versa) in historical records, which is quite understandable as both species are extremely difficult to distinguish especially from herbarium specimens. I would rather consider it a dubious identification. Apart from fine de-tails in leaves form, leaves persistency and flower, sometimes impossible to assess in habitat, the overall colour of the leaves is usually relevant: green in S. forsterianum, silvery-green in S. reflexum. Sedum forsterianum comes from Central and Western Europe.

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Sedum kimnachii Byalt (with a confusing history and still mostly known as Sedum decumbens R. T. Clausen) is simply mentioned in Wilcox (2007) in the list of vascular plants, without any comment. Not mentioned by Sykes (1992) while in Webb et al (1988) only South Island locations are indicated. NZ Plant Conservation Network indicates as the only North Island location Lower Hutt. (However, they still not distinguish between S. decumbens and S. kimnachii – the very same plant in fact, which is confusing for some enthusiasts, myself including few years ago).

How come Rangitoto? I don’t know, as there is no source known to me placing this species in Ran-gitoto or any other Hauraki Gulf island. I haven’t

Sedum kimnachii (Sedum decumbens), cultivated plant.

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seen it in Rangitoto and, without dismissing this possibility, I rather think it has slim chances to thrive on the long term in this hot and dry habitat. It is a perennial subshrub with decumbent stems, apple green to yellowish-green leaves producing profuse yellow flowers in winter. Very popular in cultivation, it only needs extended cooler and moister periods during the year. No wonder it es-caped cultivation especially in the South Island. Easy to propagate from cuttings and definitely able to self-propagate vegetatively. It is another Mexican species with doubtful origin, with much horticultural success but with no known natural habitat, probably originating from the Central Pla-teau.

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Sedum mexicanum Britton. According to Sykes (1992): “Rangitoto Wharf. A few patches in shady sites besides old houses. The plants seem to flow-er sparingly on Rangitoto but have flowered freely when taken lo Christchurch.” I haven’t seen it on Rangitoto and, to be honest, I find it too fragile to withstand the extreme heat emanated by the ba-saltic lava slabs. It might have been cultivated on the island (again, very popular in many rockeries), but little chances to survive long term. It is gener-ally considered a Mexican species, with no known

natural distribution area. However, according to Ray Stephenson (1994) this taxon might be actu-ally a cultivar of Asian origin: “It is possible that Sedum mexicanum originated from the Far East for it has no close relatives in Mexico and it has more affinity with Chinese species than anything indigenous to Central America. (…) The precise habitat of Sedum mexicanum is unknown though it is commonly grown and has escaped in several Central American countries.” Common in cultiva-tion around Auckland.

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Sedum praealtum De Candolle ssp. praealtum is another alpine species thriving at sea level in New Zealand. Cr

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Naturalized in many places in New Zealand, S. praealtum is a typical garden escape. Not sure about propagation by seed, but leaves and espe-cially broken stem fragments root easily. In Rangi-toto plants are usually scattered, growing between rocks or on shingle, or even in silty sand close to the high tide mark, in shaded positions or exposed in full sun, near Rangitoto wharf, from Islington to Yankee Wharf, and along the path to the Con-trolled Mine Base. Usually considered not a very prolific flowerer in cultivation, it is “freely flower-ing plants contrast with the other (…) stonecrops on Rangitoto.” (Sykes, 1992). Common, but rarely forming dense stands. On occasion it can form shrubby specimens, up to 50-70 cm high, espe-cially in semi-shaded and sheltered positions else-where, but I didn’t see this happening here in Ran-gitoto. Quite prone to snail damage. It also comes from Mexico. Cr

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Sedum reflexum L. is posing another challenge… Given (1984) places this plant in Rangitoto while Webb et al (1988, 1989) take a step back and re-veals the long time confusion with Sedum forst-erianum. This species is not mentioned in Sykes (1992) or any later paper in relation to Rangitoto, however, I have seen it in other locations (for in-stance The Bluff, Napier) only not in Rangitoto. It could be a dubious record, the result of an incor-rect identification; however, I cannot completely discard this species. Sedum reflexum is native to northern, central and south-western Europe. Cr

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Sedum x rubrotinctum R.T. Clausen commonly known as the Jelly bean plant, or Pork and beans is mentioned in Wilcox (2007) in the species list… and this is all I know in relation to this species in relation to Rangitoto. No other record placing it on the island. In my opinion this species is a very un-likely candidate for long term survival on overheat-ing basaltic lava substrate and prolonged draught, although it could have been cultivated here in the past. It originates from Mexico, but again, from obscure origins (Ray Stephenson, 1994, suspects it could be a horticultural hybrid, possibly Sedum pachyphyllum x Sedum stahlii). Cr

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Euphorbia milii Desmoul var. splendens (Hook.) Ursh & Leandri, the classic Crown of thorns, is mentioned by Sykes (2005) as a “minor garden escape”, “a plant in lava crevices around an old house site” – also mentioned in Wilcox (2007) in the species list with no other comment – it could be still persisting on an old house site near Isling-ton Bay. According to Sykes (2005) the species is possibly represented in New Zealand by a single clone and does not form seed. It is a shrubby, marginal succulent species, very popular in cul-tivation for more than 200 years in Europe, and fairly common in cultivation in New Zealand as well, mostly as a garden plant. Euphorbia milii var. splendens has larger or longer spines, leaves and bracts compared to the type. This species comes from Madagascar. Eu

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Pelargonium inodorum Willd. (the native Stork’s-bill) is a coast-hardy, sand binding species with succulent leaves and stems and a fleshy tap root which might have been used as food. It has an annual or biannual habit. It was mentioned by Kirk (1879), as Pelargonium australe L. var. clandestinum (L'Hérit.) Hook. f. Pelargonium inodorum is native to both Australia and New Zealand. However, “P. inodorum is a sp. of modified communities and although recorded as indigenous by previous N.Z. Flo-ras (e.g., Allan 1961), its status is doubtful. It is at least reasonably certain that the sp. has greatly increased its range and abundance in modern times.” (Webb et al, 1988). This suggests that indigenous genetic stock could have been altered by introduction of Australian genetic material. G

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Pelargonium peltatum (L.) L'Hérit. Sykes, 1992: “Islington. Very few plants in scrub near an old house site. The cultivar represented had double pink-ish mauve flowers and is also adventive elsewhere in New Zealand.” This spe-cies used to be very popular in cultiva-tion but only few escapes are known. It comes from South Africa.

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Pelargonium x asperum Willd. (P. graveolens Aiton x P. radens H. Moore) Sykes, 1992: “Islington and Rangitoto Wharf. Around a number of old house sites where it regenerates in the vicinity of the original plants. The plants on Rangitoto and else-where in New Zealand are uniform and apparently mostly spread by vegetative means. It is the com-monest of the scented leaved geraniums and is wild around the North Island coast and on some

offshore islands. The New Zealand plants resem-ble the second parent much more than the first one.” This is a complex of hybrids coming from South Africa as well. This species is important for the cosmetic industry, as essential oils produced from its flowers are used in aromatherapy and as cosmetic ingredient, but also used to be a very popular cottage garden plant. I didn’t see it being used in modern plantings. G

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Pelargonium x domesticum L. Bailey is another stem succulent species very popular in old fash-ioned gardens that managed to escape cultiva-tion, not only in Rangitoto, but in several parts of New Zealand. Mentioned by Sykes (1992) around Islington and Rangitoto wharf baches, I have seen it only in the latter location. Not numerous, but ap-parently enduring and is regenerating locally only vegetatively, and mostly relatively close to former baches or their gardens. However, I spotted few isolated plants quite far away and this suggests that there could be a suitable dispersal vector. Pel-argonium x domesticum is a very complex hybrid, incompletely known. However, its parents must have come from South Africa.

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Epidendrum cinnabarinum Lindl. (Epidendrum ibaguense Kunth in H.B.K.) I have to quote here the entire paragraph from Sykes (1992) as it contains pretty much all I know about this species in Rangitoto: “Islington. A single large tangled mat on a lava pinnacle around an old house site but apparently was no more than a relic of cultivation although showing a tendency to layer. This spe-cies and its hybrids form one of the commonest groups of epiphytic orchids in cultivation in New Zealand. The Rangitoto plant seems to belong to the species itself because its flowers resemble those on early paintings of E. cinnabarinum. Indigenous to northern S. America.” However, this species does not appear listed in Wilcox (2007)

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Peperomia urvilleana A. Rich. is a small native coastal suc-culent plant very common in North Island and only scarcely in the upper South Island (it is a bit cold sensitive), Raoul Island in the Kermadec Islands group, Norfolk and Lord Howe Islands, western Samoa and Fiji. It is relatively com-mon in Rangitoto, around Rangitoto wharf, near Flax Point, along the summit and the south-eastern coastal tracks. It spreads from seed dispersed copiously (freely flowering / setting seed some 10 months per year) but also stem frag-ments are rooting very easily. The Fijian plants are treated by some authors as var. fijiana, but this is far from being generally accepted as some diagnostic characters are rec-ognizable in plants from Auckland area (Sykes, 1992). In some databases it is a provisionally accepted name only. Peperomia urvilleana has two opposed leafs, while a very similar species, Peperomia quadrifolia (L.) Kunth, with al-most worldwide distribution has four opposed leaves at the same level of the stem.

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Aloe arborescens Miller was another favourite of old fashioned cottage gardens form New Zealand. The first specimen I saw on Rangitoto in January 2009, near Yankee Wharf, was never retrieved again being possibly completely checked by DOC. However, later on (especially 2014) I have seen some regrowth (I guess this is extremely hard to wipe out once established on the lava fields) and even a massive stand on the path between Yankee Wharf and the Controlled Mine Base (obviously an old cultivation relict that hasn’t been checked in recent years). Although typically a strong and fast grower Aloe arborescens is encountered in natural habitats in New Zealand mostly as a persistent cultivation relict, which may recover and establish from horticultural waste, but is not an aggressive colonizer. One reason is the lack of seeds in New Zealand plants, possibly due to many decades of propagation from the same clone (cuttings root inevitably). Aloe arborescens comes from South Af-rica, Malawi, Mozambique and Zimbabwe.

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Aloe brevifolia Mill. is also currently eradicated from Rangitoto according to Wilcox, 2007. No other information whatsoever, just an entry on a list. This species forms relatively large clumps and is also tough as old boots, only endures even better than A. aristata full sun exposure in Auckland’s rock gardens. It flowers in late spring to early summer. A. brevifolia comes from South Africa (Western Cape) where it is an endangered species.

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Aloe aristata Haw. (known as the Lace Aloe, or Torch plant) is currently eradicated from Rangito-to, according to Wilcox, 2007. I’m pretty confident that this species was widely cultivated on the is-land, as it used to be very common in rock gar-dens, and still is. Plants do surprisingly well out-doors in Auckland climate, even much better than in greenhouses or conservatories, despite the pro-longed winter rains. I don’t know who recorded this species in Rangitoto, but this comes as no sur-prise. Fact is it was eradicated although it wouldn’t make headlines because of its invasive behaviour. It mostly propagates locally, from detached off-sets, but generally it is a slow grower which may become overgrown by other species in unchecked gardens. It comes from South Africa and Lesotho. Xa

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Aloe ciliaris Haw. (Climbing Aloe) is referred by Sykes (1992) in “Islington. One strag-gling plant on an old garden site. (…) is only a relic of cultivation.” Sykes’ collection is dated 1989. Probably this plant has been checked by DOC long time ago, need-less to say I haven’t seen any in Rangitoto. Although it is a fast grower, being able of forming sizeable thickets in time, Aloe ciliaris typically needs a bit more moisture (and possibly warmth over winter) than available in Rangitoto. In my opinion it had anyway low survival chances here, even if assisted. It comes from South Africa.

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Aloe maculata All. (mostly referred as Aloe saponaria (Aiton) Haw. in New Zealand botanical records) is a very popular and easy-going plant, and there is no wonder that it managed to settle here. It is a quite slow growing in the harsh conditions en-countered in Rangitoto and probably with a rather low dispersal rate. Rhizomes are sent around the mother plant and even-tually a medium sized compact colony is formed.

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Contrary to cultivated plants or wild plants grow-ing in different conditions Rangitoto plants remain rather low growing, in semi-sheltered positions on lava fields. It might have been the intense heat at ground level, or the lack of water – the plants I have seen were looking rather stressed and most of them of brownish colour.

There are two distinct forms on the island, with many plants (maybe most of them) having inter-mediate features: short leaved plants, however with wide leaf base (possibly the type identified in 1883 by T. F. Cheeseman as Aloe latifolia (Haworth) Haworth), and one with much longer and narrow-er leaves. This character is usually influenced by specific exposure (or cultivation), but both forms occur in the same habitat, sometimes only meters away. I put it on a certain genetic variation. How-ever, both types have consistently flat – topped ra-cemes bearing salmon-red flowers, and the lateral teeth with a slightly orientation towards the leaf base (backwards).

Absolutely astonishing, in Rangitoto flowering

doesn’t seem to occur in every year, but rather (or much more abundant) during cooler and moister years, in late winter to late spring. Aloe maculata is here mostly forming small groups around older plants (or around already dead plants) but with-out establishing dense colonies. The plants I have seen were scattered on the eastern coast of the island, from Islington Bay wharf to Yankee Wharf and Controlled Mine Base, but also in the south-ern parts around Rangitoto wharf, mostly close to the waterline, in few distinct populations. It is quite possibly that the plant was cultivated in gar-dens and that originally it was a typical garden es-cape; however, as I haven’t seen any plants grow-ing close to abandoned baches, or their former gardens, I am pointing rather to seed dispersal by other means, at least for the newer generations.

Aloe maculata is in its natural habitat a variable plant, found in a wide range of habitats across Southern Africa, especially southern and eastern South Africa, south-eastern Botswana and Zimba-bwe. Xa

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Psilotum nudum, Islington Bay.

I won’t go into far depth accounting for the non-succulent flora of Rangitoto; however, I can’t wrap it up without briefly presenting some other very interesting plant species encountered here. Al-though a fairly new island geologically speaking, Rangitoto is prob-ably the most composite piece of land here in New Zealand, with a captivating flora.

V.Some interesting exotic & native speciestitletitle

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Anemone coronaria L. (or possibly A. pavonina L. ?) (fam. Ranunculaceae) is inconsistently mentioned as A. pavonina L. in Wilcox (2007) and as Anemone x hybrid in Miller et al (1994). The latest is definitely not the plant seen by me near Islington Bay, and in my opinion possibly not A. pavonina either, but A. coronaria. (A. pavonina is similar to A. coronaria but the flowers are smaller). However, I have my doubts. Flowers are borne on a long single stem above a relatively low rosette of leaves and are multi-coloured, red, blue, purple, pink, white… and many cultivars and hybrids have been developed

in time, since the early 1800s. It comes from the native to the Mediterranean region and Middle East (especially Turkey, Israel and Jordan). The ver-nacular name used in European cultures is Span-ish marigold. All pictures are from the same beau-tiful stand of mixed colours flowers near Islington, in an abandoned garden. This was the only place I have seen this species – but what a surprise for me! They are average self-seeders but it’s much easier to propagate them by divided tubers (some-times called “bulbs”, which is technically incorrect). They flower typically in late winter to early spring. Ra

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Clematis paniculata J.F.Gmel. (fam. Ranunculaceae) is an iconic endemic New Zealand plant with distri-bution in North Island, South Island and Stewart Is-land, and naturalized on Chatham Islands. It is a vine (climber) growing from the base of the host tree until up in its canopy (up to 12 metres above the ground), where it grows foliage and flowers. Ra

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Not parasitic, as it doesn’t damage its host in any way. There are male and female flowers on different plants, the male flowers being some-what bigger and showier. It was a ritual plant in the Maori culture, a spring harbinger, and flowers being used to make garlands. The Maori name is Puawhananga (meaning “flower of the skies”). C. paniculata has a distinct juvenile form with much narrower leaves. It flowers in August to Septem-ber, sooner or later, depending on the weather: the harder the winter, the later it flowers.

Not rare at all, but difficult to reach as it grows up high in the canopy. C. paniculata is relatively

common on Rangitoto, mostly in the scoria cone area (Wilcox, 2007), and there is where I have seen it indeed several times and in several places, but mostly growing in trees along the road from the summit to Islington (Summit Road), although the picture in Wilcox (2007) was taken in 2006 on McKenzie Bay Road, which is the south-western coastal road, quite far from the scoria cone.

Quite different from all other Clematis species from New Zealand, and almost impossible to con-fuse. A beautiful, beautiful, beautiful, discretely scented flower. My favourite, of all non-succulent plants! Ra

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Astelia solandri A.Cunn. (fam. Asteliaceae) an ev-ergreen rhizomatous perennial growing epiphytic on aging trees, on the lower parts of their trunks but here on Rangitoto mostly lithophytic. It has 1-2 m long leaves, dark green on the upper side, and silvery-green beneath. Plants are dioecious (male and female flowers on separate plants), flowers are yellowish-white and finely scented and appear in late winter to early spring, developing later round and somewhat translucent fruits, green to yellow or red-brownish. Seed dispersal is supported by fruit eating birds, here on Rangitoto especially the tui bird (Prosthemadera novaeseelandiae) and the New Zealand pigeon (Hemiphaga novaeseelandiae). Endemic to New Zealand, the plant was named after Daniel Carlsson Solander (1733 - 1782) who

was a Swedish naturalist and an avid follower of Carl Linnaeus. It is a beautiful plant with fascinat-ing, delicate flowers. In the traditional Maori cul-ture, its leaves were used in multi-coloured fibre weaving and in making shallow baskets for cook-ing or serving different meals. The crimson fruits are not only edible but have an agreeable flavour.

Very common in Rangitoto, where it grows near tracks in relatively sheltered positions in light bushy areas or surrounded by young forest type vegetation. The most impressive specimens I have seen near Rangitoto wharf and on the south-east-ern coastal track from Yankee Wharf to Rangito-to wharf, but I’m convinced there could be many more scattered in not-so accessible corners of the island. As

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Brachyglottis kirkii var. kirkii (Kirk) C.J.Webb in Connor & Edgar (= Senecio kirkii Hook.f. ex Kirk) – vernacular names are Forest tree groundsel, Kirk's daisy, Kohuhurangi – is a New Zealand (North Is-land only) endemic shrub growing to 1-2 m high and bearing up to 3 cm wide white daisy like flow-ers with yellow centre on large inflorescences (up to 20 flowers), however, it is growing mostly epiphytic. In Rangitoto, as many other epiphytes, Brachyglottis kirkii var. kirkii was forced to become a lithophyte. I have seen this species in both situations. It was named “after Thomas Kirk (18 January 1828 - 8 March 1898), a NZ botanist and lecturer in natu-ral sciences and regarded as a leader of botanical enquiry in NZ for over three decades. One of his most significant publications was Forest flora of NZ (1889) but he also contributed over 130 papers to the Transactions and Proceedings of the NZ In-

stitute and other journals.” (NZPCN) This is one of the protected species being regard-

ed in “Serious Decline” nationwide only 10 years ago, and not really recovering in recent years (“At Risk – Declining”, in 2009 and 2012) – mainly due to predation by possums, deer and goats. As a mat-ter of fact Rangitoto seems to be one of the few strongholds left, with numerous specimens out there – luckily its traditional predators have been eradicated here. I have seen this species mainly on the southern summit track, around Wilsons Gar-den and along the road between summit and Is-lington Bay. Great plant, although I’ve made a few trips across the lava fields to be able to take the close-ups.

Its leaves are quite fleshy to leathery, but not enough I guess to be technically considered a suc-culent and quite variable in shape and sometimes with loosely lobed margins. As

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Collospermum hastatum always grows close to the top of the trees, but here in Rangitoto, cov-ered mostly in bush and low young Metrosideros forest, they are often forced to grow at a lower height and in many cases they simply turn litho-phyte.

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Collospermum hastatum (Colenso) Skottsb. (fam. Asteliaceae). The view of dozens of these dioecious (male and female flowers on separate plants) nest epiphytes growing high on trees is truly spectacu-lar! … And C. hastatum is one of the biggest plants of this type, forming large and heavy clumps of strap-like arching leaves. Vernacular names are Perching lily, Kahakaha and… the Widow Maker (name given by the early European settlers) as it has the tendency to fall from the tall kauri trees on the logging workers beneath… and in those times there were still centennial kauri trees around, bearing their heavy load. C. hastatum is common in the entire North Island and in the northern tip

of the South Island. This is a very interesting phenomenon which I

have to follow up later on. As epiphytes they grow mostly on native trees, but on occasion they also reside on introduced species. Traditional seed dispersal is assured by the tui bird (Prosthemad-era novaeseelandiae) and the New Zealand pigeon (Hemiphaga novaeseelandiae) eating their fruits, but on occasion introduced birds such as Mynahs (Acridotheres tristis) do the same, but elsewhere not on Rangitoto where it is absent. The clumps hold a small water reservoir which is used as the only breeding ground by Culex asteliae, a New Zea-land endemic mosquito. As

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aeThe most interesting fact is that Calystegia soldanella (L.) R.Br. ex Roem. & Schult. (fam. Convolvulaceae) – usually growing on beaches or fore dunes in xerophytic condi-tions – has very fleshy, succulent leaves, capable to store a certain amount of water in order to overcome the draught; upslope plants growing more or less hidden between higher vegetation in moist and sheltered positions have membranous leaves (more like the other Calystegia or Convolvulus species have). On top of that its thick, fleshy roots are also designed to store precious water and nutrients. In other words this plant has defi-nitely placed a bid for succulence, but seemed to have stopped halfway through.

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Calystegia soldanella (L.) R.Br. ex Roem. & Schult. (fam. Convolvulaceae) is another occasionally sub-succulent species. Before we continue I have to clarify few things – the well known Calystegia sol-danella (Linnaeus) R. Brown (basyionym Convol-vulus soldanella L., heterotypic synonym Calyste-gia sepium var. tangerine Pau), which is in fact an invalid name (see Note 1 in Zimer, 2009b), correct-ly being referred as Calystegia soldanella Roem. & Schult., is actually a cosmopolite plant spread in both hemispheres. Calystegia soldanella is indig-enous in New Zealand (North Island, South Island, Kermadec Islands, Three Kings Island, Stewart Is-land and Chatham Islands). Therefore Calystegia soldanella is not a naturalized plant, but is not ex-

actly a pure native either, as we cannot be even sure that native stock has not been mixed in the past with overseas plants, as it happened to other relatives.

In its typical state Calystegia soldanella is a sand dune pioneer, establishing quickly in exposed po-sitions and becoming locally dominant, but less inclined to face the competition of other plants. However, in Rangitoto it is mostly populating lava blocks covered by minimal soil, sand or rock rub-ble accumulations.

It is very common and almost impossible to overlook.

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Cymbalaria muralis G. Gaertn., B. Mey. & Scherb. (fam. Scrophulariaceae) is a small herb from the Mediterranean Europe, with small snapdragon-like flowers variably coloured from white to pink to purple and blue (usually bi-colour), and scalloped leaves. Common name is Kenilworth ivy. It is typi-cally growing on rocks and walls (hence the name) and is spreading very quickly in adequate condi-tions. Quite invasive in fact, it’s been naturalized worldwide and causes problems in certain habitats as it tends to outgrow similar indigenous species. “This plant has an unusual method of propagation. The flower stalk is initially positively phototropic and moves towards the light – after fertilisation, it becomes negatively phototropic and moves away from the light. This results in seed being pushed into dark crevices of rock walls, where it is more likely to germinate and where it prefers to grow.” (Wikipedia) Otherwise a lovely plant, quite com-mon on Auckland stone walls. Sc

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It does best in lightly shaded and moist to mod-erately dry positions, and is very common on Rangitoto especially around the old baches and abandoned gardens (there’s no shortage of rock substrate, of course). Tends to die back during pe-riods of extended draught, but invariably revives during the wet seasons. Traditionally its leaves were used for salads (reportedly it has anti-scor-butic properties), although a sometimes bitter or stringent taste was reported; more, it seems to be toxic for some animals. However, its contem-porary “use” is wall cover… never seen in garden centers, but it’s almost omnipresent on old stony structures, flowering some 9-10 months in a year.

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Feesia laxa (Thunb.) Goldblatt & J.C. Manning (fam. Iridaceae) is a small corm forming geophyte, very var-iable, from Africa (from south-east to southern Africa) with red or pink and white flowers, bearing more or less visible characteristic marks, very popular ornamental known as Red flame lily or False Freesia (synonyms Anomatheca cruenta, Anomatheca laxa, Lapeirousia cruenta, Lapeirousia laxa). It has been pre-viously recorded near or west of Rangitoto wharf by E.K. Cameron in 1993 (“near start of Kowhai Track. Few plants together, flowers pale scarlet; between house sites, did not appear to be planted. Under open pohutukawa canopy.”), and was also mentioned in Wilcox (2007) in the same location, however, I have seen this species only north of Islington wharf, along the coastal track. Typically it flowers in Rangi-toto 1-2 weeks earlier than on the mainland. The plants seen by me in Rangitoto seem to be a relatively modern cultivar, and not exactly the true species, but still are beautiful and showy spring flowers. Ir

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Freesia refracta (Jacquin) Klatt. (fam. Iridaceae), the true Freesia, is growing abundantly around for-mer settlements and sometimes along the tracks, for few metres. Freely propagating by corms and seed, it is hard to stop once set foot somewhere.

Rangitoto is actually a perfect habitat for this species offering myriads of crevices where corms find shelter from the scorching summer heat, only to come to life in late winter to early spring. It comes from South Africa and has been recorded as naturalized (according to NZCPN) only in 1972, but my firm belief is that is that it must have been present on Rangitoto long before. In Wilcox (2007)

on page 20 there is a very relevant picture on the occurrence of F. refracta on the island, hundreds of flowers dotting the coastal track margins near Islington Bay. A beautiful display in late winter to early spring, in white and pastel yellow, mauve, orange, sometimes bicolour or with fine stripes! Although recorded as a true species, as with many other entries in New Zealand botanical accounts, the naturalized plants originate from the widely cultivated common freesias, which are in fact hor-ticultural products, selected cultivars or hybrids with other Freesia species. This doesn’t lessen their splendour in any way! Ir

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Nerium oleander L. (fam. Apocynaceae) had its reputation dented by the numerous “poisonous plant” allegations – no wonder, as it belongs to the Apocynaceae family, well known for including some of the most poisonous plants of the world. As someone once wrote the oleander has suffered from poor press; however, it still is highly valued by some growers and due to the many existing forms, cultivars and hybrids even an International Olean-der Society has been established. As old-fashioned cottage gardens can be still often seen in New Zea-land this plant is widespread in warmer parts of the country and managed to establish even in very small wild populations.

Nerium oleander is one of the easiest shrubs to grow and it became very popular in some warmer parts of the world. As it is not demanding, does

not need fertilizers or special soils (grows even in compacted substrates) and it thrives if given any sunny spot. The only real care that has to be taken is to pull out from time to time its suckers while young because it drains the energy of the mother plant and this is reflected by poor flowering. It is easily propagated by cuttings and rooted suckers. Seeds germinate also readily, however I think it is the harder way to propagate this plant unless you have a real call for this kind of propagation.It has a moderate range in New Zealand, being naturalized only in the warmest parts of the coun-try - Northland, greater Auckland and the Kerma-dec group of islands (Raoul Island in particular). It doesn’t occur in great numbers, but more or less isolated plants and doesn’t seem to pose any threat for natural habitats. Ap

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I don’t think that control is necessary in this case and Nerium oleander will probably remain just a colourful addition to the native flora. As I am not particularly interested in shrubs and trees I haven’t noticed this plant in natural environments until I saw it in Rangitoto. The few plants seen here are definitely garden relics, although there is at least one of them (the oleander pictured here) which was quite far and isolated from any of the former gardens or baches, along the coastal track between Islington Bay wharf and Yankee Wharf – and this one caught my attention.

Nerium oleander originates from the Mediterra-nean basin, including North Africa, and Southwest to South Asia, but has been widely cultivated for hundreds and thousands of years and has been deliberately introduced or managed to escape cul-tivation in warmer regions of the world. Ap

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Lachenalia aloides (L.f.) Asch. et Graebner (fam. Asparagaceae, sub-fam. Scilloideae) is a small bulbous perennial from Western Cape (South Africa) – vernacular is Cape cowslip - with strap-like spotted leaves and fleshy stems (merely suc-culent) bearing pendent tubular yel-low flowers, sometimes red at the tips (seen by me only rarely in Ran-gitoto plants which are mostly com-pletely golden), in late winter and spring. Not of considerable interest I guess for botanists, but quite a nice little plant which is hard to overlook when in flower. It used to be a pop-ular container or rock garden plant, and has been widely cultivated in frost free areas of New Zealand, and of course Rangitoto. It seems to be only localized for the time being, but definitely having the potential to spread slowly. Some of the plants were seen quite far from the baches or abandoned gardens. It is another geophyte speculating the myriads of tiny crevices of the lava fields. As

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Psilotum nudum (L.) P. Beauv. (fam. Psilotaceae) (the Skeleton fork fern) is a plant species to be treated with much respect ... It is limited to tropi-cal and sub-tropical regions of the globe, and is relatively common in New Zealand and fairly well represented in Rangitoto. It is in fact a living fos-sil - its origins are very old – as it is the direct de-scendant of the first vascular plants dominating the Silurian and Devonian (359-444 mil. years ago), and considered to have only very little changed or not changed at all over the last 230 million years, likely even more, although there’s no clear fossil evidence to stop controversies around. In other words, it might be older than the dinosaurs (their childhood has been definitely witnessed). It is one of the oldest unchanged organisms in the world!It is a fern and therefore is propagating by spores and, evidently, does not have flowers, or leaves,

etc. Very interesting it lacks roots too! It is fixing itself using rhizomes-like organs, also used for as-similation of nutrients through symbiosis with var-ious fungi. In tropical regions it is strictly epiphytic plant, in other cooler areas it also grows on the ground.

In Rangitoto most of them - as you can see from the photos – prefer the lithophyte path (in fact as many other typical epiphytes do here). They pre-fer rock crevices (hence the relatively large pres-ence in the island), in rather exposed positions where they don’t have competition from other plant species, although in other regions it is found in swampy areas and in all sorts of intermediate habitats. This species is not threatened nationally, but was steadily declining in later decades due to habitat loss or deteriorating habitat quality. Still common in Rangitoto and thriving! Ps

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Pulchrinodus inflatus (Hook. f. & Wilson) B.H. Al-len (fam. Pterobryaceae) was discovered and firstly described as a New Zealand moss, but it has in fact a geographically much wider distribution which includes New Caledonia and Tasmania, however, with New Zealand remaining the main distribution centre. Beautiful yellowish-green cushions grow-ing in relatively sheltered and moist pockets, not really a colonizer, but rather establishing in settled niches. It is strictly terrestrial, growing equally in moister and drier areas, between rocks and on mild slopes. It is locally abundant in maybe cou-ple of dozens of locations scattered all over New Zealand, on both main islands. My pictures do not make justice to this astonishing moss. Peculiar for this moss is that it doesn’t form sporophytes (generating in time for this reason a taxonomic back and forth) and reproduction occurs asexu-ally through apical buds. In New Zealand it occurs from sea level to roughly 900 m altitude, while in Tasmania and New Caledonia it only occurs at me-dium elevation (700 – 1100 m). Pt

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Trichomanes reniforme G. Forst. (fam. Hymeno-phyllaceae) – Kidney fern, Raurenga, is an endem-ic filmy fern and, in addition to this, technically a sub-succulent species. T. reniforme has developed a simple morphological improvement: instead of one single layer of cells the fronds are 4 to 6 cells in thickness, placed below and above a central much stronger cell layer. H

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We have here in fact a very sophisticated archi-tecture, a functional differentiation between tis-sues designed to provide structural support and tissues designed to accumulate and retain certain amounts of moisture.

This may look very petty for the entire economy of the plant, fact is that this alone allows the Kid-ney fern to store enough moisture in its fronds in order to pass more or less prolonged periods of draught or simply evade the moist habitat restric-tions and adventure in otherwise unthinkable plac-es such as semi-open lava fields. Without stomata – organs that by opening / closing in certain condi-tions can regulate the water loss – all exchanges are membranous and this implies comparatively

huge amounts of water being available to keep the ball rolling. In times of moisture deficit (usu-ally high summer) it dehydrates, only to rehydrate with the next rain. Desiccated fronds are papyrus like; well hydrated fronds are nicely green and translucent. Quite common in Rangitoto, coloniz-ing more or less sheltered groves, especially abun-dant close to Rangitoto wharf (Kidney Fern Glen), along the northern path to Wreck Bay, along the Coastal Track, near the summit and in other few spots. Grows sometimes lithophytic, sometimes epiphytic; survives in the open, but prefers filtered light and remnant moisture. Some of the largest populations I have seen anywhere in New Zea-land. It is only rarely associated with other ferns.

The translucent frond holds enough water to gap short draught periods.

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VI. notable absences from the succulent flora

Euphorbia glauca, here at Houghton Bay, Wellington

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Speaking of notable absences… I cannot ig-nore the obvious and surprising absence of few non-succulent very common spe-cies – most importantly totara (Podocarpus

totara, Podocarpaceae) and the coastal koromiko (Hebe macrocarpa, Scrophulariaceae), not only very common natives species, but also present on the neighbouring Motutapu Island. This underlines the importance of the absence of specific dispersal vectors versus proximity. Somewhat less under-standable is that important totara seed dispersal birds (such as the New Zealand pigeon and the tui bird) have been seen browsing Rangitoto, attract-ed mostly by the kowhai flowering in springtime.

On the other hand, the succulent flora of Rangi-toto is consisting mostly of adventive species, mak-ing it one of the most interesting and composite in New Zealand. Some of these species are even found naturalized only on this relatively small is-land and nowhere else in New Zealand. However, there are a few notable absences… of these two are really interesting and worthwhile discussing.First of all – Cotyledon orbiculata L. var. orbiculata, and this is highly surprising. This species – in fact

a complex of many dozens of forms (not to men-tion its varieties) of which up to a dozen or so are cultivated in Auckland area (and generally in New Zealand). Tough and hardy, does particularly well as a garden plant in rockeries or even in traditional gardens and forms plenty of highly fertile seed. In several locations throughout New Zealand it be-came a highly invasive species, replacing indig-enous coastal vegetation, in other maybe only a nuisance, but still proves that in coastal regions it is able to colonize vast areas creating dense populations. Especially if you look at the density reached elsewhere it becomes hard to believe that it couldn’t set foot here, on a real playground for invasive succulents, where competition is less in-tense.

I put it simply on the lack of dispersal vectors, in this case birds, and not any birds, but rock pi-geons (Columba livia domestica). The generally ac-cepted theory is seed dispersal by wind, and I’m not disputing that it cannot happen at least in cer-tain conditions. However, in time, looking at very obvious dispersal anomalies – such as dispersal line against the prevailing wind direction in Piha

Flowering Aeonium arboreum - here in Napier.

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- or analysing the characteristics of high infested spots – such as Napier (especially The Bluff) or Whakatane, where on the adjoining heights there are numerous feral pigeons nesting in the pigeon-holes and crevices – I realized that it has some-thing to do with the pigeons… Seeds dispersed by wind might not land always in adequate spots and receive no other logistic support. More, seeds are fine, but small, round and compact, not the really adapted for wind dispersal (gravitational, maybe?) and definitely not able to be blown by whirlwinds for tens or even hundreds of meters upwards on the rock faces. However, seeds passing through the digestive tracts of the birds (acid breaking the seed coat?) and landing together with the moist and Nitrogen rich droppings have much better chances of germination. Unfortunately (for the species) or luckily (for conservationists) there is no feral rock pigeon population on Rangitoto or flying regularly from the mainland to the island to serve as a dispersal vector.

I don’t know if C. orbiculata was ever cultivated on Rangitoto, however, this is quite possible as it used to be a very common garden plant in early to mid-20th century in Auckland. If so, wind dispersal

of the seeds wasn’t very effective. In my opinion, in this case wind doesn’t do it. It is actually funny that seeds dispersal by birds, highly considered in ridiculously long dispersal ranges, is completely ignored in this case.

Another prominently absence is in my opinion Aeonium arboreum (L.) Webb & Berth., in all its forms cultivated in New Zealand, the common green form, but also the hugely popular coloured cultivars such as ‘Atropurpureum’ or ‘Zwartkop’. It is (or at least it was) the most popular Aeonium in cultivation. As mentioned above, after early dubious records, all seem to be in agreement that Aeonium arboreum is not present on Rangitoto. I haven’t seen it, not even plants that generally look like it.

However, this species is widely naturalized elsewhere in New Zealand, especially the green form in Greater Auckland, Hawkes Bay (Napier) – together with A. arboreum ‘Atropurpureum’, Wellington – where beautiful hybrids have been recorded, Canterbury, near Christchurch – especially in Banks Peninsula, etc. It is like most Aeoniums a prolific seeder, it does wonderful in poor soils (my preferred propagation substrate

Euphorbia glauca - here at Houghton Bay, Wellington.

Cotyledon orbiculata- here in Napier. su

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is pure scoria), it proved to be successful in other areas, although not equally aggressive as A. haworthii or A. undulatum for instance, and maybe less tolerant to coastal conditions. However, I have no satisfactory explanation for this absence. It is very unlikely not to have been cultivated on the island.

Opuntioids – except for one very cryptic mention in Wilcox (2007), Opuntia monacantha – have not been recorded on Rangitoto either. In fact O. monacantha could have been noted only in relation to the intended botanical garden (site known today as Wilsons Park). No trace of it today or any mentions of other common cultivated species such as O. ficus-indica or O. robusta, successfully escaped and established elsewhere. Of course, New Zealand does not offer the conditions for a rampant invasion as it happened “over the ditch” in Australia, but still there are few pockets. Opuntioids have been widely cultivated especially in late 19th to mid-20th centuries, as for many people, along the massive Cereoids, these plants could have represented the idea of cacti, as they are resilient and accommodating. Rangitoto would be a perfect eco-climatic setup.

Euphorbia glauca G. Forst. was never recorded in Rangitoto, although it is (or was, probably better said) a fairly common native coastal plant in New Zealand (it is naturally found also on Chatham Islands). This species is considered to be “at risk –

declining” as of 2012, but more important is that populations may vary dramatically in number of individuals, depending on particular conditions. The greatest threats are browsing animals, competition from other coastal plant species and coastal developments, but according to NZPCN entire populations have been wiped out by a fungal disease, especially on South Island’s West Coast. This species is a prolific seeder (although very good germination occurs only in fresh seeds) and has also a moderate rhizomatous spreading habit, forming locally dense stands.

However, although currently extinct from the greater Auckland area where it used to be common many decades ago, E. glauca is still present on two of the Hauraki Gulf islands. Why not on Rangitoto? I don’t know.

Finally, I will mention two more absentees: Yucca gloriosa L. var gloriosa, the common Spanish dagger so widespread in coastal conditions (mostly in sand dunes or deeper soils and less on rocky substrate, this could be the explanation) and Furcraea selloa K. Koch (known as the Wild Sisal) known from many extremely resilient cultivation relicts in New Zealand.

The absence of all these species is quite remarkable and partly hard to explain, as Rangitoto knows the highest concentration of succulent species in New Zealand, both as number of species and individuals confined on a limited area.

Furcraea selloa - here at at Whangarei Heads

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Agapanthus praecox ssp. orientalis - white flowering form

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Rangitoto is not only an iconic landmark, a weekend destination for many Aucklanders, but also precious conservation land. In fact, it has become obvious that with all the pres-

sure created especially by human activities and the presence of more or less invasive unwanted organisms, it had to be unavoidable for DOC one of the main targets when it comes to conserve and rehabilitate island habitats, as they are less changed by human intervention. This is poten-tially a less difficult task and basically financially more affordable. However, for objectives of highly touristic importance neighbouring areas with high density population, such as Auckland, this be-comes more of a Fée Morgane.

There are big plans in regards to Rangitoto, re-lease of native birds, plantings of naturally rare or endangered plant species, etc., and all this has a prerequisite the eradication or at least strict con-trol of many alien plant species (most succulents here fall into this category), and stop the disper-sal of other invasive species as well. Considering all this, if successful, most succulents here are doomed to be eradicated in a not so distant future, or at least to be allowed only on limited or strictly controlled areas. To be honest, although I agree in some aspects I am sceptical in many others I won’t detail here (see also in Zimer, 2008, 2009a, 2010c) not to speak that conservation work – even if prop-erly done, which is quite a rare event as such espe-cially when relying mostly on volunteer work, can replace somewhat natural imbalances with other disproportions leading to a functionally artificial habitat anyway, in need of being maintained on the long run. Let’s not forget that Rangitoto is also a touristic attraction and you have to find a balance here. Rangitoto used to be almost from the start a

very composite piece of nature, it never was a bal-anced natural island habitat and in my opinion it will never be in a predicable time span… At least DOC has managed to stop the rampant spread of several invasive plant species (some eradicated), has managed to make Rangitoto animal pest free, these are really great achievements.

However, I am critical on the continuous drive to adopt such a hard line for the future as the costs may largely exceed the benefits. My main reproach is that at times it is such a bureaucratic approach that one would think these rehabilita-tion plans were almost designed to tick boxes and justify funding, while other more important ser-viceable areas are ignored. Why was allowed to quarry and to process rock on the island (for lo-cal utilization, this is true) if it is well known that in a such unsettled habitat dispersal of dust and generally fine particles and changes to the surface have triggered rampant dispersal of aggressive in-vaders and changes of the vegetation patterns? In a nutshell I would rather spend effort and money to fight real enemies nationwide, such as gorse (Ulex europaeus - a real pest, not just a nuisance: e.g. slowly getting out of control on the Eastern Summit Road in Rangitoto, or on the southern slopes of Whatipu, which is supposed to be a sci-entific reserve, or the heavy infestations at the foot of Bream Head, a near pristine landmark?) or exotic grasses taking over imperceptibly near pristine habitats all over New Zealand, rather than checking Aeoniums and Agaves or other more or less casuals on Rangitoto. I guess that being over-zealous in some aspects and much too tolerant in others does not help long-term overall, but only aggravates the contrasts. Between conservation and destruction there is only a fine line.

Near Yankee Wharf

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AcknowledgementsFirst of all I would like to thank Dag Panco for sparking up my interest for suc-

culent plants naturalization in New Zealand, many years ago. It just happened,

but he opened me this path. I would also like to thank Dag for the tremendous

amount of work put into this project. I would like to thank my son Vlad as he

was my travelling companion in most of the Rangitoto trips. I will cherish the

good old days, all the philosophic debates and the hilarious laughs we had!

Last but not least, I would like to thank my wife Luana for starting my Rangito-

to obsession back in 2006, when she initiated the first trip there, and for push-

ing me to put this all together… well, not a real book yet, but getting there! All

pictures by Eduart Zimer and Vlad Zimer taken in habitat on Rangitoto Island,

except where otherwise stated (e.g. cultivated, or here at...). I tried to use as

many original habitat illustrations as I could; however, I have also used on

occasion some photographs from other locations if pictures were superior or

if I didn’t encounter that particular species in Rangitoto. All maps or historic

drawings, paintings and copyrighted photographs have been used under the

Creative Commons Attribution 4.0 International license.

Selected Literature• Allan, H.H., 1961 - Flora of New Zealand Volume I: Indigenous Tracheo-

phyta - Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledons.

Botany Division, Department of Scientific and Industrial Research. Gov-

ernment Printer. Wellington. New Zealand. 1085pp.

• Butler, M., 2001 – Rangitoto Island 1866 Extent of Vegetation, 1887 &

1913 Fires. Auckland Botanical Society Journal 56(2): 84-86.

• Clarkson, B.D., 1990 - A Review of vegetation development following

recent (<450 years) volcanic disturbance in North Island, New Zealand.

New Zealand Journal of Ecology 14: 59-71.

• Court, G. D., 2000 - Succulent Flora of Southern Africa (Revised Edition).

A.A. Balkema Publishers. Rotterdam. Netherlands. 336pp.

• Department of Conservation http://www.doc.govt.nz/- last accessed

08.01.2015

• Given, D. R., 1984 - Checklist of Dicotyledons naturalized in New Zea-

land. New Zealand Journal of Botany 22:181-183.

• Healy, A.J. and Edgar, E., 1980 - Flora of New Zealand Volume III. Adven-

tive Cyperaceous Petalous and Spathaceous Monocotyledons. Botany

Division, Department of Scientific and Industrial Research, Government

Printer, Wellington, 220 pp.

• Heenan, P. B., de Lange, P. J., Glenny, D.S., Brietwieser, I., Brownsey,

P.J., and Ogle, C.C., 1999 - Checklist of dicotyledons, gymnosperms, and

pteridophytes naturalised or casual in New Zealand: additional records

1997–1998. New Zealand Journal of Botany 37: 629–642.

• Heenan, P. B., de Lange, P. J., Cameron, E. K. and Parris, B. S., 2008 -

Checklist of dicotyledons, gymnosperms, and pteridophytes naturalised

or casual in New Zealand: Additional records 2004–06. New Zealand

Journal of Botany, 46(2): 257-283.

• Howell, C. and Sawyer, J.W.D., 2006 - New Zealand Naturalised vascular

plant checklist, New Zealand Plant Conservation Network, November

2006. 60 pp.

• Howell, C., 2008 - Consolidated list of environmental weeds in New

Zealand. Science & Technical Publishing Department of Conservation,

Wellington, New Zealand. 42pp.

• International Crassulaceae Network http://www.crassulaceae.ch/de/

home - last accessed 08.01.2015

• Julian, A., 1992 - The vegetation pattern of Rangitoto. University of Auck-

land. PhD thesis. Unpublished. 297pp.

• Kirk, T., 1879 - Notes on the Botany of Waiheke Rangitoto and other

islands of the Hauraki Gulf. Transactions and Proceedings of the New

Zealand Institute 11: 444-454.

• Lancaster, T.L., 1929 - Municipal Record. Official organ of the Auckland

City Corporation of New Zealand 3(3):5-8.

• Miller, C.J., Craig, J.L. and Mitchell, N.D., 1994 - Ark 2020: A conservation

vision for Rangitoto and Motutapu Islands. Journal of The Royal Society

of New Zealand 24(1): 65-90.

• National Pest Plant Accord 2012. http://www.biosecurity.govt.nz/nppa -

last accessed 08.01.2015

• New Zealand Plant Conservation Network http://www.nzpcn.org.nz/

default.aspx - last accessed 08.01.2015

• Palmer, A.D., 1969 - Rangitoto. Auckland Botanical Society Newsletter

26(4): 7-8.

• Rangitoto Island Historic Conservation Trust http://www.rangitoto.org/

index.html - last accessed 12.01.2015

• Stephenson, R., 1994 - Sedum: Cultivated Stonecrops. Timber Press.

Oregon, USA. 355pp.

• Sykes, W.R., 1992 - Succulent Plants on Rangitoto Island. Auckland Bo-

tanical Society Journal 47(1): 6-16.

• Sykes, W.R., 2004 - Succulents misbehaving in my gardens. New Zealand

Botanical Society Newsletter 75: 16-26.

• Sykes, W.R., 2005 - Notes on Euphorbia and Crassula with a revised key

to the latter wild in New Zealand. New Zealand Botanical Society News-

letter 79: 8-16.

• Webb, C. J., Sykes, W. R. and Garnock-Jones, P. J., 1988 - Flora of New

Zealand Volume IV: Naturalised Pteridophytes, Gymnosperms, Dicotyle-

dons. Botany Division, Department of Scientific and Industrial Research.

Manaaki Whenua Press. Lincoln. New Zealand. 1365pp.

• Webb, C. J., Sykes, W. R., Garnock-Jones, P. J., Given, D.R., and Brownsey,

P.J., 1989 - Checklist of dicotyledons, gymnosperms, and pteridophytes

naturalised in New Zealand: additional records and corrections. New

Zealand Journal of Botany 27:139-162.

• Whiting, D.C., 1987 - Vegetation colonisation of Rangitoto Island: the

role of crevice microclimate. University of Auckland. M. Sc. thesis. Un-

published. 265pp.

• Wilcox, M.D. (editor), 2007 - Natural History of Rangitoto Island. Auck-

land Botanical Society. New Zealand. 192pp.

• Woolnough, A., 1984 – Rangitoto. The story of the island and its people.

Angela Woolnough. Auckland. New Zealand. 72pp.

• Wotherspoon, S. H. and Wotherspoon, J. A., 2002 - The Evolution and Ex-

ecution of a Plan for Invasive Weed Eradication and Control, Rangitoto

Island, Hauraki Gulf, New Zealand: p381-388. In Veitch, C.R. and Clout,

M.N. (editors). Turning the tide: The eradication of invasive species. Oc-

casional paper of IUCN Species Survival Commission No. 27, Invasive

Species Group, IUCN, Gland, Switzerland and Cambridge, UK. 414pp.

• Zimer, E., 2007 - Plante suculente naturalizate în Noua Zeelanda. Acc

Aztekium. (Internet – last accessed 25.06.2014).

• Zimer, E., 2008 - The naturalized Aeonium of Rangitoto Island (Hauraki

Gulf, New Zealand). International Crassulaceae Network. (Internet – last

accessed 25.06.2014).

• Zimer, E., 2009a - The succulent corner at Yankee Wharf, Rangitoto Is-

land .The New Zealand Cactus and Succulent Journal 62 (4): 114-120.

• Zimer, E., 2009b - Succulent plants from down under – Adventive Plants

(Part 8). Unpublished. 23pp.

• Zimer, E., 2010a – The adventive Crassulaceae of Rangitoto Island, Hau-

raki Gulf, New Zealand. International Crassulaceae Network. (Internet

– last accessed 25.06.2014).

• Zimer, E., 2010b – Notes on Aeonium ‘Rangitoto’ I. The New Zealand

Cactus and Succulent Journal 63(2): 37.

• Zimer, E., 2010c – The fragile boundary between conservation and

destruction on Rangitoto Island, Hauraki Gulf, New Zealand (Part 1).

Unpublished. 37pp.

• Zimer, E., 2012a – Is Horokaka (Disphyma australe ssp. australe) more

than a regional form of Disphyma crassifolium? Xerophilia 1(2):51-70.

• Zimer, E., 2012b – Aeonium ‘Rangitoto’. Xerophilia 1(3): 5-22.

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Young budding Metrosideros excelsa. This species will be always associated with Rangitoto …

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part 2.

whakaari white islandnew zealand

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Aerial photograph of White Island (Whakaari, or Whakāri) in the Bay of Plenty, The North Island, New Zealand. Note there is no steam rising from the crater lake. The coloured trail is sulphur leaking in the sea water. 20 January 2005, photo by James M. Shook. (Wikipedia)

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whakaari

Whakaari - White Island - is not the kind of South Pacific island you would like to spend your holiday on, it is mostly

barren and inhospitable. It is after all an active volcano with fumaroles, boiling mud pools, steam, gas and ash emissions and astrictive sulphur smell, rumbling and sending out tremors on a daily basis. However, my April 2014 trip to the island was quite memorable to say the least: it was my ultimate New Zealand volcanic experience. Despite being a hostile environment it is not lifeless... which was not a surprise. As a matter of fact people have worked and lived here from time to time, even in the times prior to the European colonization.

White Island volcano erupting on the 20th of August 2013. According to GeoNet the volcano erupted only for 10 minutes throwing "mud and rocks a short distance from the source, and produced large volumes of white steam. (…) A small proportion of volcanic ash was carried with the steam". Photo by Alex and Jennifer Simon.

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New Zealand’s largest volcanic structureWhakaari is an 150,000 – 200,000 years old active volcano, part of the Taupo volcanic field, 48 km off Bay of Plenty coast, opposite Whakatane. The 238 ha island is rising to 321 m above sea level and it happens to be only a small part of the volcanic complex climbing some 1,600 m from the sea bed and containing active volcanic vents up to 400 m deep underwater – it is in fact New Zealand’s largest volcanic structure. You wouldn’t have guessed that. The magma chambers lie only 1,700-3,000 m deep, depending on the eruptive state, which is really shallow as a matter of fact. It is an andesite and dacite stratovolcano, this means at least 22 layers of solified volcanic lava from previous eruptions are alternating with layers of volcanic ash deposits. This points out that the volcano has had a tortuous eruptive past: periods of high lava extrusion have swapped with explosive activity dispersing pyroclastic ashes (Dr. Richard Roscoe).

At the same time the complex is formed by two independent but overlapping stratocones: an extinct cone makes up a quarter of the island, while the rest is made up of the central cone, still active. In fact it’s not that simple as it is a very dynamic landscape indeed. Historically there have been several active subcraters (Western, Central and Eastern), the first two being the most unsettled, undergoing frequent changes in known history. Numerous vents and pits have been created in time, only to be obliterated by later eruptions or obscured by erosion. It is actually quite amazing to see relatively deep vertical gullies scoring the high slopes, carved in volcanic ash layers. Some of them seem actually quite unstable and the tragic event from 100 years ago has a very obvious explanation.

There is a long list of volcanic events of the past. However, the actual shape of the crater was largely created during the 1976-1982 eruptions and subsequently altered again between 1986-1990.

White Island seen off Ohope coast, near Whakatane

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In the centre of the crater there is an acid lake with quite volatile water levels. Truth is that 1976-1991 was the longest period of intense and almost uninterrupted volcanic activity on the island, at least in known history. It is believed that in 1991 part of the high conduit channel collapsed covering the magma chambers (only 300-400 m deep at that time) and putting the volcano to rest, not before to generate the strongest volcanic earthquake ever recorded in New Zealand. Subsequently there were other significant eruptions in 2000 (when a strombolian explosion occurred, covering the crater floor with scoriacious lava bombs) and

again in 2012/2013 while the recent background volcanic action suggests that another activity spike could be arriving soon. Gaseous emissions are mostly carbon dioxide and sulphur dioxide, but on occasion there are short explosive events, when fumaroles erupt, sending jets of hot steam into the skies and sometimes ejecting football sized rocks which can land hundreds of metres away. After the turbulent 1976-1991 period the crater lake almost disappeared, but reappeared once the volcano settled a bit and the main crater cooled down. Although the water level is fluctuating quite a lot, fresh water wells are filling the lake regularly.

White Island’s main vent during the 2000 eruption. Photo by Michael Rogers (Wikipedia)

Approaching White Island from the sea. Steam emerging from the main crater lake.

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Above left: Steam emerging from the main crater lake. Above right: Corroding equipment of the 1923 sulphur ore processing factory. Below left: Mounds of materials ejected from vents and fumaroles. Below right: The inner walls consisting partly of ashes, eroded by rain

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From humble beginnings to large scale miningIn good weather the steaming island is visible from the coast, and there’s no wonder why it always has attracted visitors. The Maori used to sail regularly to the island and gather birds and their eggs for food (there still is a large gannet breeding colony here) and also to collect sulphur which they used as fertilizer. They named the island Whakaari (actually the full name is Te Puia o Whakaari, meaning The Dramatic Volcano), also spelled Whakāri (1). Captain Cook discovered the island during his 1769 voyage and named it White Island, purely based on its appearance: surrounded by what he thought there were white clouds. He actually failed to recognize it is a volcano, with the clouds formed from the steam emissions.

The first Europeans landed on the island in 1826 and soon its economic value became very obvious. In 1830 the island was bought from the Maori but only to be sold on for several times. However, for a short time, White Island became a touristic attraction.

Boats of the Northern Star Company cruise ships brought on occasion visitors ashore for day trips. It wasn’t big business, but added a little

spin to their cruising experience I guess. The first lucrative mining operation was set up much later, in 1874, when one of the White Island co-owners started to mine small amounts of sulphur and export them to Sydney, in Australia, as fertilizer. It was a relatively small scale operation, but the potential was recognized.

In 1883 "NZ Manure and Chemical Company" was established and a sulphur processing factory was built in Tauranga. Sulphur, mined from White Island, was processed here and used mainly for producing sulphuric acid. However, this operation wasn’t long lived either. After the dramatic Mt. Tarawera eruption in 1886 (2), when huge amounts of ashes were scattered in the region, covering with a 2-3 cm thick layer even areas located at a distance of over 100 km, the mining on the island was abandoned, for fear that such a devastating eruption could take place on the island as well. Lacking the raw material, the entire business collapsed.

Production was resumed again in 1898, but after four years, during which 5,000 tons of sulphur ore were mined, the best deposits were exhausted and exploitation became uneconomical and the business was closed down once again. But not for long.

Steam rising from the main crater lake.Steam and sulphur fumes from the fumaroles.

It's not a good idea to come close to the main crater lake without the gas mask on.

Steam rising from the main crater lake.

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Big business and tragediesIn 1913 Brown and Mercer, two Brits running a Canadian company, bought White Island and established "The White Island Sulphur Co. of Vancouver". In order to cut cost this time the sulphur ore was processed directly on the island. A boiler house and several ovens were erected and sulphur was extracted and processed into a fine powder, weighted and packed into sacks. People worked and lived on the island, covering long shifts for several months at a time. During peak demand time there were up to 30 people working and living on the island. Working conditions were hazardous and work accidents were common. All metal structures (including the retorts) were corroding quite fast in this acid environment and at some stage one such retort exploded killing one of the workers. More, in order to gain access to new sulphur ore deposits on the crated floor, the acidic lake was drained. Work wasn’t a walk in the park.

Living conditions were also not optimal, as you can imagine, not to speak of the solitude. There was no drinkable water on the island. Only few people were attracted as the pay wasn’t too extravagant either. The average daily wage was 13 shillings, which in today’s money is less than 43 British pounds. However, the owners advertised worldwide that they are seeking labourers to work on a South Pacific island... a very appealing prospect for many. It is said that one foreigner tricked into a supposed exotic island life realized the truth only shortly before landing on White Island. He climbed and tied himself to the mast and refused vigorously to come down, shouting and cursing in a foreign language none of the sailors could understand. In the end they had to turn around and bring the lunatic back to the mainland.

Much later, Claude Sarich, a sulphur miner working on White Island in 1931–32, left a vivid description: "The worst hell on earth, a place where

View of the sea with Troup Head in the backgroung, steam and sulphur deposits.

Steaming vents with massive sulphur ore deposits.

The steaming crater rim. The steaming crater rim.

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rocks exploded in the intense heat, where men had to wear wool instead of cotton because cotton just fell apart in just a couple of hours, where they had to clean their teeth at least three times a day because their teeth went black, and where the land shook violently and regularly sending rocks flying through the air". So, these were the living conditions

The workers were virtually left on their own on the island. Every week or so a ship was arriving

in the bay loading the sulphur and leaving supplies for the workers. The ship couldn’t land safely and there was no proper wharf, so the ship was anchored at a certain distance and the sulphur sacks were loaded first into a dinghy and transferred onto the ship, and back the same way were transferred supplies and equipment. It was a hard work indeed which could take up most of the day. In September 1914 disaster struck all of a sudden. The supply ship transferred to the island a fresh shift on the 7thof September and when it returned on the 19th with mail and supplies (3)

they found all structures washed out to sea and no trace of the 10 workers (4). No bodies have been ever recovered, even after repeated search parties. Couple of weeks later debris of the structures (poles, railway sleeps, timber and the wreckage of the three existing dinghies) were washed out on the shore, including beaches of Tauranga. It is said that an 11th man should have been on the island, as he was recently hired as a cook for the working crew; however, the week before the tragedy

occurred, he had a change of mind and didn’t even bother to announce his employer. He simply didn’t show up and the ship left without him. However, there was one survivor – the crew’s cat Peter, later renamed Peter the Great, who was found after 21 days, starved and exhausted but otherwise fine, wandering on the opposite side of the island, not affected by the disaster. Peter the Great was brought back to the mainland and it is said that he fathered numerous descendants, all of them being considered good luck cats. Reportedly the dynasty still exists.

In the crater of White Island (c.1930s.) A worker toils at the sulphur extraction plant on White Island in the Bay of Plenty (in the late 1920s).

The steaming crater rim.

Wreckage from White Island at Tauranga, 1914.Left: The only survivor, a cat - Peter the Great. Middle: White Island products brochure c.1927.

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It is not known exactly what happened. Fact is that part of the gigantic western flank wall collapsed into the crater triggering a devastating lahar and leaving no chance for the workers to escape. It is not established if the flank wall collapsed under its own weight or if the collapse was prompted by volcanic activity. No one on the mainland was aware of the tragedy, although there were later claims that explosions have been heard and a persistent sulphur smell was in the air at the time. When the supply ship arrived on the 19th of September all they found was a site of complete devastation (5). News broke out immediately and reached Auckland on the 21st of September when an article appeared in the Evening Post. All 10 workers were supposedly dead, and the total damages were estimated at £20,000 (or $50,000), which was quite a fortune at that time. It is nevertheless strange that news of the tradegy was published only in the page 8 of the journal. Well, I guess that the first World War that just started was making the headlines.

Search parties were organized as there was still some hope. They thought the workers would have had the time to rush in the dinghies and go out at sea, a much safer option even on rough seas than staying on the island. It already happened in the 1880s when, after a small eruption, the people had enough time to jump in the dinghies and go out in the open seas.

But this time none of the missing workers was ever found, dead or alive. People must have been swept out on the sea or buried under the several metres high mud wave. It must have been so wicked because it caused metal poles to snap from their base. There is also considered that the tragedy could have happened overnight, while everybody was sleeping, so they wouldn’t have had the slightest chance. This tragedy put a brutal stop to all operations on White Island. People were probably afraid to return, or maybe the raging first World War changed priorities.

After some time, a team of scientists tried to elucidate the mystery of what could have caused the tragedy. They came to the conclusion that the western flank wall would have been weakened by erosion and riddeled by steaming vents and collapsed at some stage, possibly following a small earthquake.

This landslide would have obscured the crater lake. With all the vents being obstructed now, pressure must have been built up inside the volcano until a violent eruption sent a wave of hot mud across the plateau at high speed. If so, the people would have been warned by the first landslide and they would have had enough time to seek refuge. Instead they possibly thought that that was that and didn’t bother too much. After all they were all tough people and shaking and rumbling was every day business on the island. This we will never know.

The beginning of the column report in the Evening Postsu

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Post World War 1 revival and business winding upBut the atrocities of the first World War have dampened down the memories and the psychological effect of the 1914 White Island tragedy. In the 1920s there was a brand new dynamic world, with a booming economy and with entrepreneurs always looking for new business ventures. The sulphur deposits on White Island were still atractive. At that time New Zealand had a flourishing farming industry and fertilizers were in high demand and it seemed lucrative to revive the sulphur exploitation on White Island. In 1923 Mr. Mercer, a co-owner of the ill fated 1913 enterprise, set up the "White Island Agriculture Chemical Co. Ltd". Assisted by George Raymond Buttle, an Auckland stock exchange broker, Mercer assured a sizeable financial investment in his company and the business took off. But this venture proved to be also doomed from the start. Safety was important now, but this came at a cost. Brand new expensive equipment was also adding to the operating cost. More, sulphur extraction was more costly and less productive than initially estimated. As a result the company struggled financially from the very beginning.

But Mr. Mercer must have been a stubborn man who wouldn’t give up that easy. Pressured by unhappy shareholders he tried several methods to reduce costs or to improve eficiency. But that wasn’t enough. During the Great Depression (1929- 1933) the turnover dropped and the business went into tailspin, but a tenacious Mr. Mercer was still holding it afloat by any means. Even with the risk of an increased bad reputation. In later years he employed any method, from slightly illegal to a completely dodgy jugglery, in order to make ends meet. For instance, during the last months of sulphur mining on White Island, he ordered the sulphur sacks to be filled three quarters with volcanic ash and only one quatrer, at the top, with pure sulphur. But farmers couldn’t be fooled that easy and they would never buy again his products. That was the final straw and in 1933 the company filed for bankruptcy. During the liquidation process G.R. Buttle, the financial mastermind, purchased the island which remained in Buttle family ownership until today.

Remains of the 1923 factory and equipment (corroding quickly away) are still standing and for some very obvious reasons attract most of the visitors.

Remains of the 1923 factory and equipment

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After the second World War the scientific value of White Island was finally acknowledged. In 1953 it was declared a private scenic reserve and in 1995 access has been restricted. Unauthorized landing is not allowed, there is a daily limited number of people who can visit the island and all have to acquire permits. The time spent on the island is also limited and only small groups are allowed under constant supervision.

Risk management is paramount. Safety helmets are compulsory and everyone gets also a gas mask to use if needed (and now and again you really need one). The small groups are scattered on throughout the island, so in case of a minor volcanic event the tour operator doesn’t have all the eggs in one basket. I guess anything can happen at any time, but after visiting the island I can say that I felt safe at all times.

White Island is renowned for unexpected volcanic events. That means scientists don’t have days, weeks or even months to predict major events, but in most cases only few hours. Still time enough to evacuate the island. The volcanic activity is permanently monitored, not only for safety reasons, but also for scientific purposes. Few live cameras are covering the critical spots, temperature and composition of the gases are measured in tens of the main vents, the crater lake is also monitored and there is a seismic station on the island as well. Live data is transmitted to the mainland labs of the Institute of Geological and Nuclear Sciences and analyzed there. Any significant change in any of the measured parametres is triggering an alarm and the situation is assessed immediately. Quite interesting stuff even for a layman.

The desolated landscape and scoria formations seen through a gap in the standing walls.Below left: View of the inner slopes with steam and gases arising from miriads of fissures.Below right: Steaming fumarole near Troup Head with the sea in the background.

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This hell is not lifeless!Even if it provides a desolated landscape the island is not lifeless. In fact you are out for quite a surprise. I had my readings on the vegetation on White Island even before deciding to visit it, and even more after making that decision. In fact I was trying to be aware of things that I might have missed otherwise during the tour. The cited literature does not include references on microscopic or bacterial life, only on vertebrates and vascular plants. However, these life forms are visibly present.

I haven’t seen lichens, fungi and mosses (this does not mean that they couldn’t live on the boulders next to the shore) but definitely I have seen algae and a slimy organic film in a small waterflow originating from a geyser. This is quite surprising as the water is very acidic (pH2, same as the lemon juice) and quite hot – around 45o Celsius. Burns (1994 ex Cassie & Cooper, 1989) mentions that Cyanidium caldarium and other diatoms (monocellular algae living in large colonies) have been observed in hot water pools near the crater, so this must be what I’ve seen. The small streams

contain in a dissolved state all known chemical elements or their compounds, however, most of them in infinitesimal, merely detectable amounts.

The vascular vegetation is quite interesting. Depauperate, but one of a kind. First of all – the vegetation succession rules do not function at all here. Most of the vegetation is still in the primary succesion phase, even species that normally would be regarded as secondary or tertiary succesion species. And, on long term, essential was the struggle of species to survive, contradicting all theories of primary succesion sequence. The number of vascular plant species ever recorded on the island is very small (19 in total) and even after settled periods of the late 1800s and early 1900s no more than 10 species have been recorded in 1912 (Oliver, 1915) and no more than 13 at a time (in 1967). After few major volcanic events following since, and especially after the tumultous 1976-1991 period, the number of species found has been halved. But the very few herbs must have been available in abundance as in the early mining days even few sheep were kept (Clarkson & Clarkson, 1994 ex Parham, 1973).

Fumarole with beautifully yellow coloured sulphur deposits.Detail above: Cyanidium caldarium and other diatoms growing in the acid hot water pools and flows near the main crater.

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must have changed, seed has been produced and dispersed in the area, as I noted quite a large number of seedlings and very young plants on the slopes near Troup Head (in the continuation of the lahar plateau), but not in other sites. In the dense vegetation patches I wasn’t able to tell anyway from the distance. We didn’t sail around the island, but while leaving I noted large patches of dense scrub and young forest on the slopes between Troup Head and North East Point but also, closer to Troup Head, dead pōhutukawa trees surrounded by new growth.

However, regrowth and expansion of Metro-sideros excelsa doesn’t happen very fast. Burns (1994) provides a pertinent explanation. He

Metrosideros excelsaThe dominant species is pōhutukawa (Metrosideros excelsa) which forms dense and almost monotypic scrub and young forest patches of vegetation on the outer slopes of the cone, in sheltered positions. A 1986 survey showed that from ca. 48 ha of Metrosideros scrub and young forest half was destroyed, with older plants being dead or badly damaged but resprouting from epicormic buds (6) (Clarkson, 1990; Clarkson & Clarkson 1994). According to Burns (1994) only 5% of the Metrosideros forest survived after the initial shock. Clarkson (1990) also noted that some of the plants carried seed capsules, possibly from the December 1985 flowering, but no seedlings have been sighted. During the following years things

Established Metrosideros scrub which seems unharmed.

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observed that the apices of many epicormic shoots were dead, with a second epicormic shoots developing underneath from old wood. Such a layering of the epicromic shoots delivered a bushy growth form but at a slower pace.

An aerial photograph taken in February 2012 by the The Ardmore Pilot (above) shows the northern slopes covered by large areas of obviously expanding pōhutukawa scrub and young forest. The cause of death was hard to determine. Clarkson (1990) states there was no evident damage caused by blast or heat, with most branches remaining intact in most dead specimens. He suggests wet ashes coating leaves could interfere with vital

processes such as photosynthesis, suffocating the plants.

Clarkson (1990) also mentions early reports stating that fumes could control the distribution and extent of the Metrosideros scrub and young forest, which is quite pertinent (see the dense vegetation on the sheltered north outer slope). However, he also mentions the “acid rain” as a possible cause, but this doesn’t match in my opinion the very localized events:

I have seen an utterly destroyed pōhutukawa section only 300 metres from a thiving patch of vegetation that seemed to be completely unharmed.

Regenerating Metrosideros scrub after being wiped out.Detail right: Aerial photograph of White Island (Whakaari) in the Bay of Plenty, The North Island, New Zealand.

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Other established plants species Another frequent occurrence is Einadia trigonos ssp. trigonos, misidentified in early records as Chenopodium allanii. This is a prostrate or semi-prostrate perennial herb, often mat-forming. I have seen few patches on the outer slopes at Crater Bay and inner slopes of Troup Head of what seems to be this species. However, I was wondering why some marginal patches have a different colour but reading the description of this species I discovered that stems and leaves could be often purplish. Poa anceps and Phormium tenax are two other species that survived eruptions and all the disturbances. This pictures shows the inner rock face of the Troup Head, sparingly vegetated by patches of Einadia trigonos ssp. trigonos and the native ice plant Disphyma australe ssp. australe and few minute Poa anceps, Metrosideros excelsa and Phormium tenax individuals. The most composite piece of land I’ve seen here.

Sparingly vegetated outcrop with a surprisingly composite vegetation: Einadia trigonos ssp. trigonos, Disphyma australe ssp. australe, and few miniature specimens of Poa anceps, Metrosideros excelsa and Phormium tenax. Detail right: Anothyer slope with numerous scattered vegetation patches consisting of Einadia trigonos ssp. trigonos, Disphyma australe ssp. australe, Poa anceps, and a splendid Metrosideros excelsa young shrublet in the fore-ground

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A succulent plant: Disphyma australe ssp. australe The big expectation – quite understandable for a succulentophile – was to see with my own eyes another survivor: Disphyma australe ssp. australe. The best succulent colonizer ever! This is the only other species noted in each of the 6 vegetation surveys since 1912 to 1990. I knew there are large masses surrounding the large gannet breeding colony on the old camp site plateau (Ohauora), so my first care before landing was to locate it. It wasn’t hard at all as the green patches were visible

from miles so to speak. I have never seen such a large patch of Disphyma in my life, and I’ve seen a few. In the photos you can’t really tell (so you have to trust me) but the binoculars offered me a spectacular view. Unfortunately only few birds where at the colony at that time. Burns (1994) confirms this is a monotypic vegetation patch.

The massive Disphyma mats at the gannet breeding colony called into question another myth about Disphyma - that acid bird droppings, when washed out by heavy rain, can quickly destroy massive patches of plants. I was really split, it

A thriving Disphyma australe ssp. australe specimen growing between boulders. Above left: D. australe ssp. australe was thriving when growing in a layer of mineral rich volcanic ash capable of retaining a bit of moisture... Above right: … but seemed to be very stressed when growing on concrete slabs of the ore processing factory.

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could have made sense for some plants but not necessarily for Disphyma. I previously saw rather small patches of Disphyma in similar situations (notably at Muriwai) but there was still room for doubt in my mind. Now, seeing this I am convinced that, on the contrary, Disphyma may even benefit from the acid and high Nitrogen content of the bird droppings. It surely survived also the “acid rain” or similar events on the island.

But still I wanted to see them close. Almost immediately after landing at Crater Bay and climbing up the plateau I noted the first patches, small but relatively numerous, growing between boulders or in the remains of the 1923 factory. Some were happy (with plenty of moisture available between and under the boulders) some were particularly stressed, especially few patches growing in cracks, with virtually no soil available, in the ruins of the former factory. I don’t know if lack of moisture was the only reason for their

state, or gusts of acid fumes could have played an important role here. As mentined above, few were also growing on the inner rock face of Troup Head.

I haven’t seen any flowers, of course highly unlikely at this time of the year (April, which is autumn in the southern hemisphere) but few seed capsules were visible. Only a few – pointing out maybe the lack of pollinators – but definitely seed has been scattered in the area in the past and will be also scattered in the future. Another observation – this local form is the biggest I have seen in this species so far, having strong stems and longer and thicker leaves than usual. The stems are only just a bit reddish on occasion (reduced amounts of betanine) which suggests that flowers could be white, not the usual pale pink. This I don’t know for sure. After Metrosideros excelsa this is the second species forming here monotypic vegetation patches and seems to be growing almost everywhere near the shore.

Disphyma australe ssp. australe, particularly stressed specimens.

Disphyma australe ssp. australe growing between boulders. A perfect setup: moisture accumulations in the mineral rich volcanic ashes and acidic environment (substrate included).

A Disphyma australe ssp. australe mound consisting of two distinct plants, growing between boulders on a substrate consisting mostly of fist sized stones and rock rubble.

A Disphyma australe ssp. australe very stressed when growing on concrete slabs of the ore processing factory

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The odd casualsBurns (1994) found in a partial survey of the flora during his December 1993 trip no bryophytes, lichens or terrestrial algae, and only 4 of the vascular plant species listed by Clarkson & Clarkson (1994). He also couldn’t find Paronychia brasiliana, a small adventive herb found during the 1990 survey at Crater Bay, suggesting that this species must have been introduced by the visitors (perhaps via earth traces on the shoe soles) but couldn’t survive in such a harsh environment. This could have been the case with several other species seen on and off, such as Cakile maritima (recorded only in 1949), Cirsium vulgare (recorded only in 1967), Coniza albida (recorded in 1949 and 1967) and Coronopus didymus (recorded only in 1967). Of all, Cakile maritima has actually the biggest chances to set foot on White Island, as its seeds can be dispersed

by sea currents (I have seen this species on Ohope beach, near Whakatane).

A special discovery of the 1990 survey was Asplenium northlandicum - probably a recent introduction as well although common in North Island coastal habitats.

Burns (1994) observed it on the cliffs at Troup Head so this could be another “touristic” introduction. In 1985, at the site of a dead Metrosideros excelsa forest a single fern Histiopteris incisa managed to survive, only to disappear completely in 1990 (Clarkson, 1990; Clarkson & Clarkson, 1994). However, Burns (1994) reports that during the partial survey Paul Jensen rediscovered Histiopteris incisa in its original 1985 location. He also mentions several Phormium tenax growing on the northern slopes in steep gullies or on rocks, that were observed from the sea.

Cakila maritima - here at Opoutere, Coromandel - was recorded only once in 1949 on White Island.

Asplenium northlandicum - here at Karekare, Waitakere - was recorded in 1990 and 1994 near Troup Head.

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A surprising wildlifeWildlife is also very limited as number of species, but quite surprisingly. During the visit I observed a butterfly and my son Vlad a couple more, but to our disappointment we were not able to take pictures. It was simply mesmerizing to see such delicate creatures flying above the barren land. I guess there is enough vegetation on the island to support insect life, but we haven’t been actually there and didn’t notice any other insects. I wonder how they could survive so close to the crater lake, where we had to put our gas masks on at times.

Seabirds such as the Austalasian gannet (Morus serrator) and Grey-faced petrel (Pterodroma macroptera) have breeding colonies on the island, but except few gannets guarding the deserted colony I haven’t seen any. Such a remote island is actually an ideal breeding ground. But more incredible is the passerine fauna. In times of low volcanic disturbances the European sparrow

(Passer domesticus) and Chaffinch (Fringilla coelebs), both introduced species, have been reported to populate the island. I haven’t seen any but I guess they are spending their time mostly in the dense Metrosideros scrub and young forest.

Especially the presence of the sparrow is quite surprisingly as it usually lives close to human settlements. However, this indicates that substantial food resources must be available on White Island. The Chaffinch’s diet consists more of seeds and vegetal materials, while chicks are fed almost exclusively on insects.

Both passerines are terrestrial insectivores and that gives us a hint in regards to the food availability in vegetated areas of the island. As mentioned above, we’ve seen butterflies! Kiore, the Polinesian rat (Rattus exulans) is alo present here, quite common near seabird colonies as they usually prey their eggs, even if their diet is more varied.

A helicopter resting on the desolated plateau.

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Life has to hang on... or start all over again!White Island gives you another perspective on how resilient life can be. I can’t stop comparing White Island to Rangitoto, a very young volcanic island in the Hauraki Gulf, only 7-800 years old, but already settled. As volcanic activity (small gas and ash emissions) stoppend competely only in the late 1700s we can consider that the vegetation and fauna of Rangitoto is merely 250-350 years old. Probably Rangitoto would have looked the same in those early days. The only difference is that White Island volcano wasn’t put at rest yet and life has to hang on and start more or less all over again after every significant volvanic event.

A last look to the steam emissions while sailing along the coast.

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Literature:• Burns, B. (1994) Botanical notes on a trip to

White Island (Whakaari), 27 November 1993. New Zealand Botanical Society Newsletter, No. 35, March 1994: 8-9.

• Clarkson, B.D. (1990) A Review of vegetation development following recent (<450 years) volcanic disturbance in North Island, New Zealand. New Zealand Journal of Ecology, Vol. 14: 59-71.

• Clarkson, B.D. & Clarkson, R.C. (1994) Vegetation decline following recent eruptions on White Island (Whakaari), Bay of Plenty, New Zealand. New Zealand Journal of Botany, Vol. 32:21-36.

• Cole, J.W. & al. (1995) Volcanic hazards at White Island. http://www.wi.co.nz/hazards.htm (last retrieved 28.04.14).

• Cole, J.W. & al. (2000) Magma Origin and Evolution of White Island (Whakaari) Volcano, Bay of Plenty, New Zealand. Journal of Petrology, Vol. 41, No. 6: 867-895.

• Oliver, W.R.B. (1915) The vegetation of White Island, New Zealand. Journal of the Linnaean Society of London, Botany 43: 41-47.

• Scott, B. & Rosenberg, M. (2007) White Island Tour: Products and processes of recent activity. Presented during the Geological Society of New Zealand & New Zealand Geophysical Society joint Annual Conference, Tauranga, 2007. Compiled by Ursula Cochran and Annie Cervelli.

Other Internet Resources:• Ecosystems-guides.com (last retrieved

29.04.14).• Institute of Geological and Nuclear Sciences

(GNS Science) White Island Volcano Fact Sheet (last retrieved 28.04.14).

• John Seach / White Island Volcano (last retrieved 28.04.14).

• Kevin Boon The White Island eruption (last retrieved 28.04.14).

• New Zealand Volcanoes (last retrieved 28.04.14).

• Dr Richard Roscoe / Photovolcanica (last retrieved 28.04.14).

• Stephanie Smith - White Island: A place of hope and despair (2012) (last retrieved 28.04.14).

• The Ardmore Pilot Stories from the sky. White Island Scenic (2012). (last retrieved 28.04.14).

• Te Ara - the Encyclopedia of New Zealand (last retrieved 28.04.14).

All pictures by Vlad Zimer and Eduart Zimer, except where otherwise stated. All copyrighted photographs have been used under the Creative Commons Attribution 4.0 International license.

Notes:(1) Some sources give another translation of the

name - “that which can be made visible”. The name is very adequate but this translation is totally inaccurate. The island becomes invisible in hazy days indeed, and can be clearly seen (including the perpetual surrounding clouds) in good weather.

(2) The 1886 Mt. Tarawera eruption killed 153 people covered in boiling mud and hot ashes.

(3) Some sources (e.g. Dr Richard Roscoe / Photovolcanica.com) indicate 17th and 25th the dates of the last departure and arrival respectively of the supply ship but this couldn’t have been possible as the news was published in the Evening Post on the 21st of September. More, the journal reports: "There is some uncertainty as to the actual date of the disaster, but it would seem to have occurred either on Thursday, 10th September, or on Friday, 11th September".

(4) Other sources indicate that 11 people died in the disaster, but once again the Evening Post claims "There is grave reason for supposing that ten lives have been lost (...)". All nominal lists I have consulted include only 10 names.

(5) The chain of events, as related by Kevin Boon: On the 10th of September black smoke was seen rising from the island and a strong smell of sulphur reached the mainland. There have been few small earthquakes and a river near Te Teko began to boil all of a sudden. On the 15th of September Albert Mokomoko, the skipper of a pilot launch from Opotiki, sailed to the island, not because there were concerns about the safety of the workers, but because it was a scheduled trip. As the sea was rough he couldn’t come ashore. He signaled but there was no response. He couldn’t see on the 50 metres high plateau where the factory was situated. On the 19th of September Albert Mokomoko returned and was able to row a dinghy ashore. Realising the disaster he then rushed to the mainland to get help.

(6) Epicormic buds lie dormant beneath the bark, their growth suppressed by hormones from active shoots higher up the plant. Under certain conditions, they develop into active shoots, such as when damage occurs to higher parts of the plant, or light levels are increased following removal of nearby plants. Epicormic buds and shoots occur in many woody species, but are absent from many others, such as most conifers. (Wikipedia)

A landslide on the outer slopes with steam rising from the cracks.

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This memory will last forever ...

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The 60 foot launch is waiting for us to step aboard.

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Farewell, Whakaari!

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